Terapias cognitivas y conductuales de "tercera generación" versus tratamiento habitual para la depresión
Resumen
Antecedentes
Las denominadas terapias cognitivas y conductuales de "tercera generación" representan una nueva generación de terapias psicológicas que se utilizan cada vez más en el tratamiento de los trastornos psicológicos. Sin embargo, todavía son inciertas la efectividad y la aceptabilidad de las terapias cognitivas y conductuales de tercera generación (TCC) como tratamiento para la depresión aguda.
Objetivos
1. Examinar los efectos de todas las TCC de tercera generación en comparación con condiciones control como tratamiento habitual / lista de espera / atención placebo / placebo psicológico para la depresión aguda.
2. Examinar los efectos de diferentes enfoques de las TCC de tercera generación (tratamiento de aceptación y compromiso, entrenamiento de compasión, psicoterapia analítica funcional, tratamiento de conducta dialéctica, terapia cognitiva basada en la práctica reflexiva, activación conductual prolongada y terapia metacognitiva) en comparación con condiciones control como tratamiento habitual / lista de espera / atención placebo / placebo psicológico para la depresión aguda.
3. Examinar los efectos de todas las TCC de tercera generación en comparación con diferentes tipos de comparadores (tratamiento habitual, ningún tratamiento, lista de espera, atención placebo, placebo psicológico) para la depresión aguda.
Métodos de búsqueda
Se hicieron búsquedas en el registro especializado del Grupo Cochrane de Depresión, Ansiedad y Neurosis (Cochrane Depression, Anxiety and Neurosis Group) (CCDANCTR hasta el 01/01/12), que incluye ensayos controlados aleatorios relevantes de The Cochrane Library (todos los años), EMBASE (1974‐), MEDLINE (1950‐) y PsycINFO (1967‐). También se hicieron búsquedas de estudios adicionales, publicados y no publicados en CINAHL (mayo de 2010), en PSYNDEX (junio de 2010) y en las listas de referencias de los estudios incluidos y revisiones relevantes. Se realizó una búsqueda actualizada en CCDANCTR restringida a términos de búsqueda relevantes para las TCC de tercera generación en marzo de 2013 (CCDANCTR hasta el 01/02/13).
Criterios de selección
Ensayos controlados aleatorios que compararon las TCC de tercera generación con tratamientos control para la depresión aguda en adultos.
Obtención y análisis de los datos
Dos revisores de forma independiente identificaron los estudios, evaluaron la calidad de los ensayos y extrajeron los datos. Cuando fue necesario se estableció contacto con los autores de los estudios para obtener información adicional. La calidad de las pruebas se calificó mediante el método GRADE.
Resultados principales
En la revisión se incluyeron cuatro estudios pequeños (224 participantes). Se proporcionó poca información acerca del proceso de asignación de los participantes a los grupos. Ninguno de los estudios utilizó evaluadores de resultado independientes y las pruebas indicaron que los investigadores prefirieron los tratamientos activos. Los cuatro estudios examinaron varios enfoques de TCC de tercera generación (activación conductual prolongada, aceptación y compromiso con el tratamiento y entrenamiento competitivo de la memoria) y condiciones control. Ninguno de los estudios realizó evaluaciones de seguimiento. Los resultados mostraron una diferencia significativa en las tasas de respuesta clínica a favor de las TCC de tercera generación en comparación con el tratamiento habitual (tres estudios, 170 participantes, cociente de riesgos [CR] 0,51; intervalo de confianza [IC] del 95%: 0,27 a 0,95; muy baja calidad). No se encontraron diferencias significativas en la aceptabilidad del tratamiento según las tasas de abandonos entre las TCC de tercera generación y el tratamiento habitual (cuatro estudios, 224 participantes, CR 1,01; IC del 95%: 0,08 a 12,30; muy baja calidad). Ambos análisis mostraron heterogeneidad estadística significativa.
Conclusiones de los autores
Pruebas de muy baja calidad indican que las TCC de tercera generación parecen ser más efectivas que el tratamiento habitual en el tratamiento de la depresión aguda. El número muy pequeño de estudios disponibles y los diferentes tipos de intervenciones y comparadores control, junto con las limitaciones metodológicas, no permite establecer conclusiones acerca del efecto de dichas terapias a corto plazo o en un plazo más prolongado. La popularidad cada vez mayor de las TCC de tercera generación en la práctica clínica refuerza la importancia de completar estudios adicionales sobre las TCC de tercera generación en el tratamiento de la depresión aguda, a corto y a largo plazo, que proporcionen pruebas de efectividad a los elaboradores de políticas, los médicos y los usuarios de los servicios.
PICOs
Resumen en términos sencillos
Terapias cognitivas y conductuales de "tercera generación" versus tratamiento habitual para la depresión
La depresión mayor es un trastorno muy frecuente en el que los pacientes presentan constantemente ánimo decaído y pérdida de interés en las actividades placenteras, acompañados de diversos síntomas que incluyen pérdida de peso, insomnio, fatiga, pérdida de energía, culpa indebida, concentración deficiente y pensamientos mórbidos relacionados con la muerte. Las terapias psicológicas son una alternativa importante y popular a los antidepresivos para el tratamiento de la depresión. Durante el siglo pasado se desarrollaron muchos enfoques diferentes de terapia psicológica, incluida la terapia conductual, la cognitivo‐conductual (TCC), la TCC de "tercera generación", las terapias psicodinámicas, humanísticas e integradoras.
Esta revisión se centró en los enfoques de TCC de tercera generación, un grupo de terapias psicológicas dirigidas al proceso de los pensamientos (en lugar de a su contenido, como en la TCC) para ayudar a los pacientes a ser conscientes de sus pensamientos y aceptarlos de una manera no crítica. El objetivo de la revisión fue determinar si las TCC de tercera generación fueron efectivas y aceptables para los pacientes en la fase aguda de la depresión. La revisión incluyó cuatro estudios con un total de 224 pacientes. Los estudios examinaron tres formas diferentes de TCC de tercera generación que incluyeron la activación conductual prolongada (dos estudios), el tratamiento de aceptación y compromiso (un estudio) y otra forma de TCC de tercera generación llamada entrenamiento competitivo de la memoria (un estudio). Tres de los estudios compararon las TCC de tercera generación con condiciones control habituales. El cuarto estudio comparó el tratamiento de aceptación y compromiso con la condición placebo psicológico. Los resultados indicaron que las TCC de tercera generación fueron efectivas a corto plazo para tratar la depresión. Sin embargo, la calidad de las pruebas fue muy baja debido al escaso número de estudios / participantes incluidos en la revisión, junto con los diferentes grupos de clientes, intervenciones y condiciones control utilizados, así como la preferencia posible de los investigadores hacia los tratamientos activos, lo que no permite establecer conclusiones confiables. También es notable que ninguno de los estudios consideró el efecto a largo plazo de las TCC de tercera generación. Debido a la popularidad cada vez mayor de los enfoques de TCC de tercera generación en la práctica clínica, se le debe dar prioridad a la realización de estudios adicionales para establecer si estos enfoques son más útiles que otras terapias psicológicas para el tratamiento de los pacientes con depresión aguda.
Authors' conclusions
Summary of findings
| Third wave CBT versus TAU for depression | ||||||
| Patient or population: depression | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Control | Third wave CBT | |||||
| Clinical non‐response at post‐treatment | Study population | RR 0.51 | 170 | ⊕⊝⊝⊝ | ||
| 800 per 1000 | 408 per 1000 | |||||
| Moderate | ||||||
| 688 per 1000 | 351 per 1000 | |||||
| Treatment acceptability (dropout) at post‐treatment | Study population | RR 1.01 | 224 | ⊕⊝⊝⊝ | ||
| 206 per 1000 | 208 per 1000 | |||||
| Moderate | ||||||
| 42 per 1000 | 42 per 1000 | |||||
| Clinical non‐remission at post‐treatment | Study population | RR 0.77 | 140 | ⊕⊝⊝⊝ | ||
| 953 per 1000 | 734 per 1000 | |||||
| Moderate | ||||||
| 938 per 1000 | 722 per 1000 | |||||
| Depression levels at post‐treatment | Mean depression levels at post‐treatment in the intervention groups were | 211 | ⊕⊝⊝⊝ | SMD ‐1.12 (‐1.53 to ‐0.71) | ||
| Anxiety levels at post‐treatment—behavioural activation vs TAU Beck Anxiety Inventory (BAI) | Mean anxiety levels at post‐treatment—behavioural activation vs tau in the intervention groups was | 30 | ⊕⊝⊝⊝ | |||
| Social adjustment levels at post‐treatment— behavioural activation vs TAU Work and Social Ajustment Scale (WSAS) | Mean social adjustment levels at post‐treatment—behavioural activation vs tau in the intervention groups was | 38 | ⊕⊝⊝⊝ | |||
| *The basis for the assumed risk (eg, the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the risk ratio of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence. | ||||||
| aMethod of sequence generation/allocation concealment unclear. As with all psychological therapy trials, blinding of clinicians/participants was not achievable. The risk of bias was assessed as high for researcher allegiance and as unclear for therapist qualifications. | ||||||
Background
Description of the condition
Major depression is characterised by persistent low mood and loss of interest in pleasurable activities, accompanied by a range of symptoms, including weight loss, insomnia, fatigue, loss of energy, inappropriate guilt, poor concentration and morbid thoughts of death (APA 2000). Somatic complaints are also a common feature of depression, and people with severe depression might develop psychotic symptoms (APA 2000).
Depression is the third leading cause of disease burden worldwide and is expected to show a rising trend over the next 20 years (WHO 2004; WHO 2008). A recent European study has estimated the point prevalence of major depression and dysthymia (a mild long‐term form of depression) at 3.9% and 1.1%, respectively (ESEMeD/MHEDEA 2004). As the largest source of non‐fatal disease burden in the world, accounting for 12% of years lived with disability (Ustun 2004), depression is associated with marked personal, social and economic morbidity and loss of functioning and productivity and creates significant demands on service providers in terms of workload (NICE 2009). Depression is also associated with a significantly increased risk of mortality (Cuijpers 2002). The strength of this association, even when confounders such as physical impairment, health‐related behaviours and socio‐economic factors are taken into account, has been shown to be comparable with, or greater than, the strength of the association between smoking and mortality (Mykletun 2009).
Description of the intervention
Clinical guidelines recommend pharmacological and psychological interventions, alone or in combination, in the treatment of moderate to severe depression (NICE 2009). The prescribing of antidepressants has increased dramatically in many Western countries over the past 20 years, mainly with the advent of selective serotonin reuptake inhibitors and newer agents such as venlafaxine, and antidepressants continue to be the mainstay of treatment for depression in healthcare settings (Ellis 2004; NICE 2009).
Whilst antidepressants are of proven efficacy in acute depression (Cipriani 2005; Guaiana 2007; Arroll 2009; Cipriani 2009; Cipriani 2009a; Cipriani 2009b), adherence rates remain very low (Hunot 2007; van Geffen 2009), in part because of patients' concerns about side effects and possible dependency (Hunot 2007). Furthermore, surveys consistently demonstrate patients' preference for psychological therapies over antidepressants (Churchill 2000; Riedel‐Heller 2005). Therefore, psychological therapies can provide an important alternative or adjunctive intervention for depressive disorders.
A diverse range of psychological therapies is now available for the treatment of common mental disorders (Pilgrim 2002). Psychological therapies may be broadly categorised into four separate philosophical and theoretical schools, comprising psychoanalytic/dynamic (Freud 1949; Klein 1960; Jung 1963), behavioural (Watson 1924; Skinner 1953; Wolpe 1958), humanistic (Maslow 1943; Rogers 1951; May 1961) and cognitive approaches (Lazarus 1971; Beck 1979). Each of these four schools incorporates several differing and overlapping psychotherapeutic approaches. Some psychotherapeutic approaches, such as cognitive analytic therapy (Ryle 1990), explicitly integrate components from several theoretical schools. Other approaches, such as interpersonal therapy for depression (Klerman 1984), have been developed to address characteristics considered to be specific to the disorder of interest.
Increasing interest in the role of cognition gave rise to a ‘cognitive revolution’ in the field of psychology in the 1970s (Mahoney 1978). The most influential approaches were rational emotive behaviour therapy (Ellis 1962), cognitive behaviour modification (Meichenbaum 1977) and cognitive therapy (Beck 1979). The latter developed as an approach to understanding and treating depression. However, both Beck and Ellis acknowledged the value of behaviour therapy (Rachman 1997), and during the 1980s and 1990s, the two approaches were merged to form cognitive‐behavioural therapy (CBT).
CBT is generally regarded as a family of allied therapies (Mansell 2008) that draw on a common base of behavioural and cognitive models of psychological disorders and utilise a set of overlapping techniques (Roth 2008). In CBT, cognition is central to the treatment of psychological disorders, with emotions and behaviour thought to be mediated by cognitive processes. The fundamental aim of CBT is to identify unhelpful cognitions or ‘negative automatic thoughts' derived from long‐standing negative beliefs/assumptions about the self, other people or the world. The CBT model proposes that by challenging their meaning and eliciting more realistic thoughts and assumptions, emotions and behaviour can be changed (Clark 1995). An extensive evidence base is available on the effectiveness of CBT, which is recommended as the first‐line psychological therapy approach for depression (NICE 2009).
Although the evolution of CBT over the past three decades has tended to overshadow approaches that are more behavioural in nature, evidence supporting purely behavioural approaches has continued to emerge. The findings from Jacobson 1996, a component analysis trial of CBT, suggested that behavioural components alone might work just as well as CBT. These findings revitalised interest in purely behavioural treatments for depression and the development of a more fully realised behavioural intervention based on a contextual approach (Martell 2001).
Prompted by continuing debate in this area, a recent systematic review of 17 randomised controlled trials (RCTs) demonstrated equivalence between CBT and behavioural therapy in terms of depression recovery rates, symptom levels and participant dropout (Ekers 2008). Proponents of a new generation of behavioural therapies, the ‘third wave’ of CBT (Hayes 2004; Hofmann 2010), have suggested that rational challenging of thoughts (a principal feature of CBT interventions) is less important than was believed (Longmore 2007) and have sought new strategies by which change can be achieved (Segal 2002). Whilst differing perspectives on which approaches should be categorised as key third wave interventions continue to be put forth (Hofmann 2010), those frequently described by experts in the field as third wave include acceptance and commitment therapy (ACT) (Hayes 2004), compassionate mind training (CMT) (Gilbert 2005), functional analytic psychotherapy (FAP) (Kohlenberg 1991), metacognitive therapy (MCT) (Wells 2008), mindfulness‐based cognitive therapy (MBCT) (Teasdale 1995), dialectical behaviour therapy (DBT) (Linehan 1993) and the expanded model of behavioural activation (BA) (Martell 2001) (see Types of interventions section for a detailed description of each type of therapy).
How the intervention might work
Third wave CBT approaches conceptualise cognitions and cognitive thought processes as psychological or ’private' events (Hayes 2006; Hofmann 2008) and target the emotional response to the situation, focusing primarily on the function of cognitions, such as thought suppression (trying to suppress distressing thoughts) or experiential avoidance (trying to avoid any thoughts, feelings and memories that are causing distress) (Hofmann 2008). This contrasts with traditional CBT, which links thoughts, feelings and behaviours and targets the situation or trigger that generates the emotional response, encouraging cognitive appraisal of these triggers and focusing on changing the content of cognitions.
Third wave CBT approaches use strategies such as mindfulness exercises (eg, body scan, mindfulness of senses meditation), acceptance of unwanted thoughts and feelings and/or cognitive defusion (stepping back and seeing thoughts as just thoughts) to elicit change in the thinking process and reduce symptoms of depression. Whilst third wave CBT methods are more often delivered in an experiential rather than didactic manner (Hayes 2004), features of traditional behavioural and cognitive therapies, such as goal setting, exposure and skills acquisition (Hayes 2006), continue to play an important role in helping to reduce depressive symptoms.
Why it is important to do this review
Corrigan 2001 suggested that proponents of third wave CBT approaches were ‘getting ahead of the data'. However, over the past twelve years, an increasing number of third wave CBT trials have been conducted, and the findings have been summarised in several systematic reviews. For example, Hayes and colleagues conducted a narrative review across all conditions/disorders to provide empirical support for dialectical behaviour therapy (DBT) (a treatment used most commonly for borderline personality disorder), functional analytic psychotherapy (FAP) and acceptance and commitment therapy (ACT), but no meta‐analyses were conducted (Hayes 2004). Another systematic review of mindfulness‐based cognitive therapy (MBCT) focused on prevention of relapse or recurrence of major depression (Coelho 2007). Ost 2008 undertook a review and meta‐analysis of third wave CBT approaches for any disorder compared with treatment as usual or any other intervention, and drew attention to the ‘less stringent’ research methodology used in third wave treatment RCTs. However, for each third wave approach, effect sizes were calculated across disorders, rather than by individual disorder. Other reviews of psychological therapies for depressive disorders have not attempted to differentiate between CBT and third wave CBT approaches (Churchill 2001; Cuijpers 2008).
Amongst CBT practitioners, much interest has been expressed in the application of third wave CBT approaches, and the updated National Institute for Health and Care Excellence treatment guidelines for depression (NICE 2009) have already recommended MBCT specifically for preventing depression in patients who have had three or more episodes of depression. Although these guidelines also recommend the use of behavioural activation (BA) for moderate to major depressive disorder, they acknowledge that the evidence for BA is currently less robust. Furthermore, the reviews upon which the recommendation for BA was based, in keeping with the approach of other recent systematic reviews, combined studies using purely behavioural therapy with those using an ‘extended’ behavioural activation approach (Churchill 2001; Cuijpers 2007; Cuijpers 2008; Ekers 2008; NICE 2009), the latter of which is increasingly regarded as a third wave CBT intervention because of its explicit focus on moving attention away from depressive 'ruminative' thoughts (Addis 2004).
Given the popularity of third wave CBT approaches and the growing body of evidence, a comprehensive review of the effectiveness and acceptability of third wave CBT interventions for depression is required to inform clinical practice and future clinical guideline development. This review serves as part of a programme of 12 reviews covering behavioural, cognitive‐behavioural, psychodynamic, interpersonal, cognitive analytic and other integrative, humanistic and third wave cognitive and behavioural psychological therapies, all compared with treatment as usual or with one another.
Objectives
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To examine the effects of all third wave CBT approaches compared with treatment as usual/waiting list/attention placebo/psychological placebo control conditions for acute depression.
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To examine the effects of different third wave CBT approaches (ACT, compassionate mind training, functional analytic psychotherapy, dialectical behaviour therapy, MBCT, extended behavioural activation and metacognitive therapy) compared with treatment as usual/waiting list/attention placebo/psychological placebo control conditions for acute depression.
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To examine the effects of all third wave CBT approaches compared with different types of comparators (treatment as usual, no treatment, waiting list, attention placebo, psychological placebo) for acute depression.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials (RCTs) were eligible for inclusion in this review. Trials employing a cross‐over design were included in the review (whilst it is acknowledged that this design is rarely used in psychological therapy trials), but only data from the first active treatment phase were used. Cluster RCTs were also eligible for inclusion.
Quasi‐randomised controlled trials, in which treatment assignment is decided through methods such as alternate days of the week, were not eligible for inclusion.
Types of participants
Participant characteristics
Studies of men and women aged ≥ 18 years were included. A Cochrane review on psychotherapy for depression in children and adolescents (< 18 years) has been undertaken separately and is soon to be published (Watanabe 2004). The increasing prevalence of memory decline (Ivnik 1992), cognitive impairment (Rait 2005) and multiple comorbid physical disorders/polypharmacy (Chen 2001) in individuals over 74 years of age may differentially influence the process and effect of psychological therapy interventions. Therefore, to ensure that older patients are appropriately represented in the review (Bayer 2000; McMurdo 2005) an upper age cut‐off of < 75 years was used (when a study may have included individuals ≥ 75, we included it so long as the average age was < 75), and a previously published Cochrane review on psychotherapeutic treatments for older depressed people (Wilson 2008) is being updated concurrently by the review authors.
Setting
Studies could be conducted in primary care and community‐based settings, or in secondary or specialist settings, and included referrals as well as volunteers. Studies involving inpatients were excluded. Studies that focused on specific populations— nurses, care givers, depressed participants at a specific workplace—were included if all participants met the criteria for depression.
Diagnosis
We included all studies that focused on acute phase treatment of clinically diagnosed depression.
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Studies adopting any standardised diagnostic criteria to define participants suffering from an acute phase unipolar depressive disorder were included. Accepted diagnostic criteria included Feighner criteria, Research Diagnostic Criteria and criteria of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM‐III) (APA 1980), DSM‐III‐Revised (R) (APA 1987), DSM‐Fourth Edition (IV) (APA 1994), DSM‐IV‐Text Revision (TR) (APA 2000) and International Classification of Diseases, Tenth Edition (ICD‐10) (WHO 1992). Earlier studies may have used ICD‐Ninth Edition (9) (WHO 1978), but ICD‐9 is not based on operationalised criteria, so studies using ICD‐9 were excluded from this category.
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Mild, moderate and severe depressive disorders are all included in primary care (Mitchell 2009; Rait 2009; Roca 2009). To fully represent the broad spectrum of severity of depressive symptoms encountered by healthcare professionals in primary care, studies that used non‐operationalised diagnostic criteria or a validated clinician or self‐report depression symptom questionnaire, such as the Hamilton Rating Scale for Depression (Hamilton 1960) or the Beck Depression Inventory (Beck 1961), to identify depression caseness as based on a recognised threshold, were included. However, it was planned to examine the influence of including this category of studies in a sensitivity analysis.
Accepted strategies for classifying mild, moderate and severe depression on the basis of criteria used in the evidence syntheses underpinning the NICE 2009 guidelines for depression were used when possible.
Studies focusing on chronic depression or treatment resistant depression (ie, studies that list these conditions as inclusion criteria) were excluded from the review. Studies in which participants were receiving treatment to prevent relapse after a depressive episode (ie, where participants were not depressed at study entry) were also excluded. Treatments for chronic depression and treatment‐resistant depression will be covered in separate Cochrane reviews.
Studies of people described as ‘at risk of suicide’ or with dysthymia or other affective disorders such as panic disorder were included if participants met the criteria for depression as stated above, but otherwise were excluded.
We did not include subgroup analyses of people with depression selected from people with mixed diagnoses because such studies would be susceptible to publication bias (the study authors reported such subgroup studies because the results were "interesting"). In other words, we included such studies only if the inclusion criteria for the entire study satisfied our eligibility criteria.
Comorbidity
Studies involving participants with comorbid physical or common mental disorders were eligible for inclusion as long as the comorbidity was not the focus of the study. In other words, we excluded such studies that focused on depression among individuals with Parkinson's disease or after acute myocardial infarction but accepted studies that may have included some participants with Parkinson's disease or with acute myocardial infarction.
Types of interventions
Experimental interventions
For the purposes of the current version of the review, the key criterion for categorising a CBT approach as third wave was that the intervention focused on modifying the function of thoughts rather than on modifying their content. Third wave CBT approaches eligible for inclusion were grouped into seven main categories, according to the theoretical principles set out by trial authors, as follows.
Acceptance and commitment therapy
In acceptance and commitment therapy (ACT) (Hayes 1999; Hayes 2004), therapists aim to transform the relationship between the experience of symptoms and difficult thoughts/feelings, so that symptoms no longer need to be avoided and become just uncomfortable transient psychological events (Harris 2006). In this way, symptom reduction becomes a by‐product of treatment (Harris 2006). Clients are encouraged to develop psychological flexibility through six core principles: cognitive defusion (perceiving thoughts, images, emotions and memories as what they are, rather than what they appear to be); acceptance (allowing these to come and go without struggling with them); contact with the present moment (awareness of and receptiveness to the here and now); use of the observing self (accessing a transcendent sense of self); personal values (discovering what is most important to one's true self); and committed action (setting goals according to values and carrying them out responsibly) (Hayes 1999). In terms of committed action, ACT uses methods in line with traditional behaviour therapy, such as exposure, skills acquisition and goal setting.
Compassionate mind training
The key principles of compassionate mind training (CMT), also known as compassion‐focused therapy (Gilbert 2005; Gilbert 2009), involve motivating individuals to care for their own well‐being, to become sensitive to their own needs and distress and to extend warmth and understanding towards themselves (Gilbert 2009). By developing this style of thinking, individuals may promote the generation of prosocial behaviours that others are more likely to engage with and reward (Allen 2005). Within the therapeutic relationship, the client is encouraged to employ self‐soothing actions whilst engaging in CBT techniques, compassionate meditation and imagery.
Functional analytic psychotherapy
In functional analytic psychotherapy (FAP), therapists regard cognition as a form of covert behaviour (the activity of thinking, planning, believing and organising) (Kohlenberg 1991), with the relationship between cognition and behaviour seen as a sequence of two behaviours. Major FAP enhancements to CBT include the use of an expanded rationale for the causes and treatment of depression. Based on the premise that the closer in time and place a behaviour is to its consequences, the greater will be the effect of those consequences, the client‐therapist relationship is used as an in vivo teaching opportunity to highlight processes occurring during therapy and link these with situations in day‐to‐day life (Kohlenberg 2002).
Behavioural activation
The original behavioural activation (BA) approach manualised by Jacobson 1996 includes teaching relaxation skills, increasing pleasant events and providing social and problem‐solving skills training; this is regarded as a traditional behavioural therapy model. More recently, the BA approach has been extended by Martell 2001 by building on the original behavioural models of depression (Lewinsohn 1974) and introducing a contextual approach to depression. The extended BA model suggests that just as avoidance maintains anxiety, avoidant coping patterns (withdrawal from situations and people) maintain depressed mood, and, therefore, avoidant coping is targeted as a primary problem. After functional analysis, in which a detailed assessment of how an individual maintains depressive behaviour is carried out, the individual is taught to formulate and accomplish behavioural goals and is encouraged to move attention away from prevailing negative thoughts towards direct, immediate experience (Hopko 2003). Traditional behavioural therapy strategies such as activity charts, relaxation training and frequent pleasant events are also used (Dobson 2001).
A second BA approach, behavioural activation treatment for depression (BATD) (Lejuez 2001), proposes that depression is maintained through the use of reinforcers such as increased social attention and escape from aversive tasks. After functional analysis, as described in the extended BA model above, access to reinforcements such as sympathy and escape from responsibility is weakened, and healthy behaviour is systematically activated through the use of goal setting and increased activities (Hopko 2003a).
Metacognitive therapy
Metacognitive therapy (MCT) for depression (Wells 2008; Wells 2009) is based on the premise that depression is maintained by problematic and difficult to control thinking patterns dominated by rumination and excessive self‐focused attention on thoughts and feelings. Depression is maintained and intensified by activation of rumination and patterns of attention. MCT incorporates attention training (ATT) as a means of increasing awareness of thinking and regaining flexible control over it. The programmed practice of ATT serves to counteract depressive inertia through the provision of a set of daily exercises, which consist of actively listening and focusing attention in the context of simultaneous sounds presented at different loudness and spatial locations. MCT also focuses on reducing rumination and unhelpful coping behaviours, and modifies positive (eg, 'thinking about the causes of depression will help me prevent it') and negative (eg, 'there's nothing I can do about my thoughts') metacognitive beliefs about rumination. Although MCT is commonly regarded as a third wave CBT approach, Hofmann 2008 reports that Adrian Wells does not view it as such.
Mindfulness‐based cognitive therapy (MBCT)
Mindfulness‐based cognitive therapy (MBCT) has been designed as a manualised group‐skills training programme intended to address vulnerability between episodes of recurrent major depression (Williams 2008). MBCT combines cognitive therapy principles with the practice of mindfulness meditation, in which close attention is paid to the present moment, whilst thoughts, feelings and body sensations are noted with an attitude of curiosity and non‐judgement. This non‐reactive stance creates the possibility of working more helpfully with sadness, fear and worry—emotions that are central to preventing depression. Segal 2002 and colleagues have suggested that the intensity of negative thinking and low concentration experienced by people with acute depression may make it difficult for these individuals to fully participate in MBCT. For these reasons, MBCT has not yet been evaluated as a treatment for acute depression. However, studies of MBCT will be included in this review if, in the future, they are used/modified for the treatment of acute depression.
Dialectical Behaviour Therapy (DBT)
DBT was originally developed as a treatment for chronically suicidal or self‐injurious women with borderline personality disorder (Linehan 1993; Koons 2001). However, the coping skills that serve as an essential component of DBT can be conceptualised as skills that are useful for managing life, independent of diagnosis; recently, standard DBT has been modified for use with depressed older adults (Lynch 2000). Skills hypothesised to be particularly relevant in treating this population include acceptance of elements of life that cannot be changed (radical acceptance), increased awareness without judgement (mindfulness), attentional control (mindfulness), better tolerance of pain (distress tolerance), acting opposite to depressive urges (opposite action) and increased interpersonal effectiveness (Lynch 2003). Although DBT is commonly regarded as a third wave CBT approach, Hofmann 2008 noted that Marsha Linehan herself does not view it as a form of third wave CBT, but rather as a form of CBT that includes acceptance strategies.
Control comparators
In each study, descriptions of the control conditions were scrutinised to ensure that they did not comprise an active psychological therapy treatment. Control comparators were categorised as follows.
Treatment as usual (TAU)
In this condition, participants could receive any appropriate medical care during the course of the study on a naturalistic basis, including pharmacotherapy and/or psychological therapy, as deemed necessary by the clinician. Standard care, usual care and no treatment conditions were also included in this category.
Waiting list (WL)
A commonly used ‘treatment as usual’ consists of randomly assigning participants to active intervention groups or a control group and providing the active intervention to both groups, while delaying delivery of the intervention to the control group until after participants in the intervention group have completed treatment. As in TAU, participants in the WL condition could receive any appropriate medical care during the course of the study on a naturalistic basis.
Attention placebo (AP)
This was defined as a control condition that is regarded as inactive by both researchers and participants in a trial.
Psychological placebo (PP)
This was defined as a control condition in a trial that is regarded by researchers as inactive but is regarded by participants as active.
We planned to document additional naturalistic treatment(s) received by participants in both control and active comparisons for each included study.
Format of psychological therapies
The psychological therapy intervention was required to be delivered through face‐to‐face meetings between participant and therapist. Interventions in which face‐to‐face therapy was augmented by telephone or Internet‐based support were included in the review. Psychological therapy approaches conducted on an individual or group basis were eligible for inclusion. The number of sessions was not limited, and we accepted psychological therapy interventions delivered in a single session.
Excluded interventions
The earlier model of behavioural activation (BA) developed and tested by Jacobson 1996 was defined primarily by the proscription of cognitive interventions (Dimidjian 2006), and does not include more contemporary procedures such as identifying and understanding the functional aspects of behaviour change (Martell 2001). For the purposes of this review, this earlier version of BA was classified as a comparator behavioural therapy intervention.
Counselling interventions traditionally draw from a wide range of psychological therapy models, including person‐centred, psychodynamic and cognitive‐behavioural approaches, applied integratively, according to the theoretical orientation of practitioners (Stiles 2008). Therefore, studies of counselling were usually included in the integrative therapies reviews. However, if the counselling intervention consisted of a single discrete psychological therapy approach, it was categorised as such, even if the intervention was referred to as 'counselling'. If the intervention was manualised, this informed our classification.
Psychological therapy models based on social constructionist principles (that focus on the ways in which individuals and groups participate in the construction of their perceived social reality), including couples therapy, family therapy, solution‐focused therapy (de Shazer 1988), narrative therapy, personal construct therapy, neuro‐linguistic programming and brief problem‐solving (Watzlavick 1974), were excluded. These therapies work with patterns and dynamics of relating within and between family, social and cultural systems to create a socially constructed framework of ideas (O'Connell 2007), rather than focusing on an individual's reality. Previously published Cochrane reviews on couples therapy for depression (Barbato 2006) and family therapy for depression (Henken 2007) will be updated concurrently.
Studies of long‐term, continuation or maintenance therapy interventions designed to prevent relapse of depression or to treat chronic depressive disorders were excluded from the review. Similarly, studies of interventions designed to prevent a future episode of depression were excluded.
Guided self‐help, in which the practitioner provides brief face‐to‐face non‐therapeutic support to participants who are using a self‐help psychological therapy intervention, were excluded, as were bibliotherapy and writing therapies.
Psychological therapy that was provided wholly by telephone or over the Internet was not eligible for inclusion.
Studies of dual modality treatments, in which participants are randomly assigned to receive a third wave cognitive and behavioural psychotherapy intervention combined with pharmacological treatment in comparison with a treatment as usual control condition, were excluded from the current review and will be examined in a separate programme of reviews on combination treatments for depression.
Component or dismantling studies, in which the effectiveness of individual components of a third wave CBT approach is investigated, were not included. It was planned to extract data from these studies for inclusion in a separate overview of psychological therapies for depression, in which multiple treatments meta‐analysis (MTM) will be used to compare the relative effectiveness of all psychotherapies, regardless of whether they have been directly compared in direct RCTs. If data were sufficient, we planned to use the MTM model proposed in Welton 2009 to allow conclusions to be drawn regarding which components, or combinations of components, are most effective in reducing depressive symptoms. See 'Unit of analysis issues' for further detail on MTM.
Types of outcome measures
Primary outcomes
1. Treatment efficacy: the number of participants who responded to treatment, as determined by changes in Beck Depression Inventory (BDI) (Beck 1961), Hamilton Rating Scale for Depression (HAM‐D) (Hamilton 1960) or Montgomery‐Asberg Depression Rating Scale (MADRS) (Montgomery 1979) scores, or in scores from any other validated depression scale. Many studies define response as 50% or greater reduction on BDI, HAM‐D, etc., with some studies defining response by using Jacobson's Reliable Change Index; we accepted the study authors' original definition. If the original authors reported several outcomes corresponding with our definition of response, we gave preference to BDI as a self‐rating scale and to HAM‐D as an observer‐rating scale.
2. Treatment acceptability: the number of participants who dropped out of psychological therapy for any reason.
Secondary outcomes
3. The number of participants who remitted while receiving treatment, based on the endpoint absolute status of participants, as measured by the Beck Depression Inventory (BDI) (Beck 1961), the Hamilton Rating Scale for Depression (HAM‐D) (Hamilton 1960), the Montgomery‐Asberg Depression Rating Scale (MADRS) (Montgomery 1979) or any other validated depression scale. Examples of definitions of remission include 10 or less on BDI, 7 or less on HAM‐D or 10 or less on MADRS; we accepted the study authors' original definition. If the original authors reported several outcomes that corresponded with our definition of response, we gave preference to BDI as a self‐rating scale and to HAM‐D as an observer‐rating scale.
4. Improvement in depression symptoms, based on a continuous outcome of group mean scores at the end of treatment using BDI, HAM‐D, MADRS or any other validated depression scale.
5. Improvement in overall symptoms, as determined by using the Clinical Global Impressions scale (CGI) (Guy 1976).
6. Improvement in anxiety symptoms, as measured using a validated continuous scale, either assessor‐rated, such as the Hamilton Anxiety Scale (HAM‐A) (Hamilton 1959) or self‐report, including the Trait subscale of the Spielberger State‐Trait Anxiety Inventory (STAI‐T) (Spielberger 1983) and the Beck Anxiety Inventory (BAI) (Beck 1988).
7. Adverse effects, such as completed suicides, attempted suicides and worsening of symptoms, when reported, were summarised in narrative form.
8. Social adjustment and social functioning, including Global Assessment of Function (Luborsky 1962) scores, when reported, were summarised in narrative form.
9. Quality of life, as assessed with the use of validated measures such as Short Form (SF)‐36 (Ware 1993), Health of the Nation Outcome Scales (HoNOS) (Wing 1994) and World Health Organization Quality of Life (WHOQOL) (WHOQL 1998), when reported, were summarised in narrative form.
10. Economic outcomes (eg, days of work absence/ability to return to work, number of appointments with primary care physician, number of referrals to secondary services, use of additional treatments), when reported, were summarised in narrative form.
Timing of outcome assessment
Post‐treatment outcomes and outcomes at each reported follow‐up point were summarised. When appropriate, and if the data allowed, outcomes were categorised as short term (up to 6 months post‐treatment), medium term (7 to 12 months post‐treatment) and long term (longer than 12 months).
Search methods for identification of studies
Electronic searches
The Cochrane, Depression, Anxiety and Neurosis Review Group's Specialised Register (CCDANCTR)
We searched two clinical trials registers created and maintained by the Cochrane Depression, Anxiety and Neurosis Group (CCDAN)—the CCDANCTR‐Studies Register and the CCDANCTR‐References Register—in June 2010, and updated searches were carried out in April 2011 and February 2012 (Register up to date as of 01/01/12), using an extensive list of search terms for a programme of reviews on all psychological therapies for depression. An updated search restricted to search terms relevant to third wave CBTs was conducted in March 2013 (Register up to date as of 01/02/13).
References to trials for inclusion in the Group's registers are collated from routine (weekly) searches of MEDLINE, EMBASE and PsycINFO, quarterly searches of the Cochrane Central Register of Controlled Trials (CENTRAL) and additional ad hoc searches of other databases (PSYNDEX, LILACS, AMED, CINAHL). These searches employ generic terms for depression, anxiety and neuroses; together with sensitive (database specific) RCT filters. Details of CCDAN's generic search strategies can be found on the Group‘s website.
References to trials are also sourced from international trials registers via the World Health Organization’s trials portal (http://apps.who.int/trialsearch/); drug companies; and handsearching of key journals, conference proceedings and other (non‐Cochrane) systematic reviews and meta‐analyses.
CCDANCTR‐Studies Register
The CCDANCTR‐Studies Register contains more than 11,000 trials for the treatment or prevention of depression, anxiety and neurosis. Each trial has been coded using the EU‐Psi coding manual (as a guide) and includes information on intervention, condition, comorbidities, age, treatment setting, etc.
The studies register was searched using the following search terms:
Condition = (depress* or dysthymi*) and Intervention = (*therap* or training).
CCDANCTR‐References Register
The CCDANCTR‐References Register contains bibliographic records of reports of trials coded in the CCDANCTR‐Studies Register, together with several other uncoded references (total number of records > 31,500). This register was searched using a comprehensive list of terms for ‘psychotherapies’, as indicated in Appendix 1. Records already retrieved from the search of the CCDANCTR‐Studies Register were de‐duplicated.
The update search employed the following list of terms for third wave CBT therapies.
Title/Abstract/Keywords = depress* AND Free‐Text = (mindfulness* or “third wave” or third‐wave or (*therap* and (acceptance* or commitment*)) or experiential or (cognitive* and (restructur* or defusion)) or (behavio* and (activation or modification)) or (thought* and suppress*) or rumination).
CINAHL and PSYNDEX
In addition to CCDANCTR, we also searched CINAHL in May 2010 and PSYNDEX in June 2010 (see Appendix 2).
No restriction on date, language or publication status was applied to the searches.
Searching other resources
Reference lists
The references of all selected studies were searched for additional published reports and citations of unpublished studies. Relevant review papers were checked.
Personal communication
Subject experts were contacted to check that all relevant studies, published and unpublished, had been considered for inclusion.
Other websites
A website related specifically to mindfulness‐based therapies (http://www.mindfulexperience.org/) was searched.
Data collection and analysis
Selection of studies
Two review authors (RC and VH) examined the abstracts of all publications obtained through the search strategy. Full articles of all studies identified by either of the review authors were then obtained and inspected by the same two review authors to identify trials meeting the following criteria.
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Randomised controlled trial.
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Participants had depression diagnosed by operationalised criteria.
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Any third wave CBT approach (ACT, compassionate mind training, functional analytic psychotherapy, extended behavioural activation model, metacognitive therapy, MBCT or DBT) compared with non‐treatment, waiting list control or treatment as usual.
Conflicts of opinion regarding eligibility of a study were discussed with a third review author after the full paper had been retrieved and consultation with the study authors sought, if necessary, until consensus was reached. External subject or methodological experts were consulted as necessary.
Data extraction and management
Data from each study were extracted independently by two review authors. Any disagreement was discussed with an additional review author, and, when necessary, the authors of the studies were contacted for further information.
Information related to study population, sample size, interventions, comparators, potential biases in the conduct of the trial, outcomes including adverse events, follow‐up and methods of statistical analysis was abstracted from the original reports into specially designed paper forms and then was entered onto a spreadsheet.
Waiting list controls
A commonly used ‘treatment as usual’ is to randomly assign participants to active intervention groups and control groups, and then provide the active intervention to both groups while delaying delivery of the intervention to the control group until after those in the intervention group have completed treatment. Thus both groups receive the active intervention but at different times. Sometimes trialists describe this as a ‘waiting list control’, or control participants are placed ‘on a waiting list’.
Data are collected at baseline, when groups are randomly assigned, and at the ‘end‐of‐treatment’, at which point participants in the active intervention group stop receiving the active intervention and participants on the waiting list start to receive the active intervention. Follow‐up of participants may be provided at time points after the end of treatment.
For studies such as th ese, we included data up to the time point at which the waiting list participants started to receive treatment. Follow‐up data for these participants were not used. Inclusion of follow‐up data could introduce bias, as the intervention was not provided as originally allocated at the point of randomisation, and participants might no longer be comparable. For instance, baseline risk for participants who received delayed treatment might have changed (eg, participants may be more depressed).
Main comparisons
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Third wave CBT versus treatment as usual
Assessment of risk of bias in included studies
Risk of bias was assessed for each included study using The Cochrane Collaboration's 'Risk of bias' tool (Higgins 2008a). The following six domains were considered.
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Sequence generation: Was the allocation sequence adequately generated?
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Allocation concealment: Was allocation adequately concealed?
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Blinding of participants, personnel and outcome assessors for each main outcome or class of outcomes: Was knowledge of the allocated treatment adequately prevented during the study?
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Incomplete outcome data for each main outcome or class of outcomes: Were incomplete outcome data adequately addressed?
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Selective outcome reporting: Are reports of the study free of any suggestion of selective outcome reporting?
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Other sources of bias: Was the study apparently free of other problems that could put it at high risk of bias? Additional items to be included here are therapist qualifications, treatment fidelity and researcher allegiance/conflict of interest.
A description of what was reported to have happened in each study was provided, and a judgement on the risk of bias was made for each domain within and across studies, based on the following three categories.
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Low risk of bias.
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Unclear risk of bias.
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High risk of bias.
Two review authors independently assessed the risk of bias in selected studies. Any disagreement was discussed with a third review author. When necessary, study authors were contacted for further information. All risk of bias data were presented graphically and described in the text. Allocation concealment was used as a marker of trial quality for the purposes of undertaking sensitivity analyses.
Measures of treatment effect
Continuous outcomes
Where studies used the same outcome measure for comparison, data were pooled by calculating the mean difference (MD). When different measures were used to assess the same outcome, data were pooled with standardised mean difference (SMD) and 95% confidence intervals (95% CIs) calculated.
Dichotomous outcomes
These outcomes were analysed by calculating a pooled relative risk (RR) and 95% CIs for each comparison and were presented in this form for ease of interpretation.
Unit of analysis issues
Cluster‐randomised trials
Cluster‐randomised trials were to be included as long as proper adjustment for the intracluster correlation could be conducted according with theCochrane Handbook for Systematic Reviews of Interventions (Higgins 2008).
Cross‐over trials
Trials employing a cross‐over design were to be included in the review, but only data from the first active treatment phase were used.
Studies with multiple treatment groups
Multiple‐arm studies (those with more than two intervention arms) can pose analytic problems in pair‐wise meta‐analysis. Had we found studies with two or more active treatment arms to be compared against treatment as usual, data were to be managed in this review as follows
Continuous data
Means, SDs and numbers of participants for all active treatment groups were to be pooled across treatment arms as a function of the number of participants in each arm to be compared against the control group (Law 2003; Higgins 2008; Higgins 2008b).
Dichotomous data
Data from relevant active intervention arms were to be collapsed into a single arm for comparison against the control group, or the control group was to be split equally between treatment groups.
Multiple treatment meta‐analysis
One method that retains the individual identity of each intervention and allows multiple intervention comparisons to be made, without the need to lump or split intervention arms, is a multiple treatment meta‐analysis (MTM) (Lu 2004; Caldwell 2005; Cipriani 2009b). MTM (also known as mixed treatment comparison or network meta‐analysis) refers to ensembles of trial evidence in which direct and indirect evidence on relative treatment effects is pooled. The objective of an MTM is to combine all the available trial evidence into an internally consistent set of estimates while respecting the randomisation in the evidence. An MTM provides estimates of the effect of each intervention relative to every other, whether or not they have been directly compared in trials. One can also calculate the probability that each treatment is the most effective. We did not intend to use an MTM in this review, as we were unlikely to have sufficient data for the analysis. However, this review forms part of a series of 12 reviews that have contributed studies to an overview of reviews (Becker 2008; Higgins 2008b) in which MTM is being used as the main analytic strategy.
Dealing with missing data
Missing dichotomous data were managed through intention‐to‐treat (ITT) analysis, in which it was assumed that participants who dropped out after randomisation had a negative outcome. It was also planned to calculate best/worse case scenarios for the clinical response outcome, in which it would be assumed that dropouts in the active treatment group had positive outcomes and those in the control group had negative outcomes (best case scenario), and that dropouts in the active treatment group had negative outcomes and those in the control group had positive outcomes (worst case scenario), thus providing boundaries for the observed treatment effect. If a large amount of information was missing, these best/worst case scenarios were to be given greater emphasis in the presentation of results.
Missing continuous data were either analysed on an endpoint basis, including only participants with a final assessment, or analysed by using the last observation carried forward to the final assessment (LOCF), if LOCF data were reported by the trial authors. When standard deviations (SDs) were missing, attempts were made to obtain these data by contacting trial authors. When SDs were not available from trial authors, they were calculated from P values, t‐values, confidence intervals or standard errors, if these were reported in the articles (Deeks 1997).
When a vast majority of actual SDs were available and only a minority of SDs were unavailable or unobtainable, it was planned to use a method for imputing SDs and calculating percentage responders; the method devised by Furukawa and colleagues (Furukawa 2005; Furukawa 2006; da Costa 2012) was used. If this method was employed, data would be interpreted with caution and the degree of observed heterogeneity would be taken into account. A sensitivity analysis would also be undertaken to examine the effect of the decision to use imputed data.
When additional figures were not available or obtainable and it was not deemed appropriate to use the Furukawa method described above, the study data were not included in the comparison of interest.
Assessment of heterogeneity
Statistical heterogeneity was formally tested using the Chi2 test, which provides evidence of variation in effect estimates beyond that of chance. Because the Chi2 test has low power to assess heterogeneity when a small number of participants or trials are included, the P value was conservatively set at 0.1. Heterogeneity was also quantified using the I2 statistic, which calculated the percentage of variability due to heterogeneity rather than to chance. We expected, a priori, that considerable clinical heterogeneity would be noted between studies, and so I2 values in the range of 50% to 90% were considered to represent substantial statistical heterogeneity and were to be explored further if sufficient studies were identified for inclusion. However, the importance of the observed I2 depended on the magnitude and direction of treatment effects and the strength of evidence for heterogeneity (Higgins 2003; Deeks 2008). Forest plots generated in RevMan 5 now provide an estimate of tau2, the between‐study variance in a random‐effects meta‐analysis. To provide an indication of the spread of true intervention effects, we also used the tau2 estimate to determine an approximate range of intervention effects using the method outlined in Section 9.5.4 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2008). This was to be done only for the primary outcomes.
Assessment of reporting biases
As far as possible, the impact of reporting biases was minimised by undertaking comprehensive searches of multiple sources (including trial registries), increasing efforts to identify unpublished material and including non–English language publications.
We tried to identify outcome reporting bias in trials by recording all trial outcomes, planned and reported, and noting where outcomes were missing. When we found evidence of missing outcomes, we attempted to obtain any available data direct from the authors.
When sufficient numbers of trials allowed for a meaningful analysis, funnel plots were to be constructed to establish the potential influence of reporting biases and small‐study effects.
Data synthesis
Given the potential heterogeneity of psychological therapy approaches for inclusion, together with the likelihood of differing secondary comorbid mental disorders in the population of interest, a random‐effects model was used in all analyses.
Subgroup analysis and investigation of heterogeneity
Clinical heterogeneity
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Baseline depression severity: The severity of depression on entry into the trial was expected to have an impact on outcome. Heterogeneity analyses categorised baseline severity as mild, moderate or severe.
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Number of sessions: Differences in the numbers of therapy sessions received were likely, and this was expected to affect treatment outcomes. Numbers of sessions were categorised as 1 to 7 sessions, 8 to 12 sessions, 13 to 20 sessions and more than 20 sessions.
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Type of comparison: The type of comparator used was likely to influence the observed effectiveness of the intervention. When possible, comparators were categorised as waiting list, treatment as usual/usual care, attention placebo or psychological placebo.
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Strength of therapeutic alliance/perceived therapist empathy, based on validated measures such as the Barrett‐Lennard Relationship Inventory (Barrett‐Lennard 1986) or the Working Alliance Inventory (Horvath 1986): When reported, this information was summarised in narrative form.
In addition to the above analyses, when appropriate, small‐study effects and potential publication bias were examined using funnel plots.
Sensitivity analysis
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Fidelity to treatment: Studies that did not assess fidelity to the psychological therapy model(s) under evaluation through assessment of audiotapes or videotapes of therapy sessions were to be excluded.
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Study quality: Allocation concealment was to be used as a marker of trial quality. Studies that did not use allocation concealment were to be excluded.
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Trials in which missing data were imputed were to be excluded.
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Trials that included the use of antidepressant treatment (naturalistic use; combination treatment used in both psychological therapy arms) were to be excluded.
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Trials included in the review after post hoc decisions were made about their eligibility as third wave CBT approaches were to be excluded.
Summary of findings table
A summary of findings table was produced to present the main findings of the review; it includes a summary of the quality of evidence, the magnitude of effects of psychological therapy interventions examined and a summary of available data on main outcomes. Findings are expressed as measures of risk ratio and absolute risk for the main outcomes of clinical response and treatment acceptability, as well as for the secondary outcomes of remission and depression levels (Higgins 2011).
Results
Description of studies
Results of the search
We conducted full psychotherapy searches in June 2010, and updated searches were carried out in April 2011 and February 2012 (CCDANCTR to 01/01/12). After removing duplicates, we identified 6710 records that were relevant for the programme of reviews on all psychological therapies for depression. We excluded 6524 records on the basis of information provided in the titles and abstracts. We read the full text of 186 studies to assess their eligibility. A total of 122 studies were judged as eligible for inclusion in the programme of reviews (Figure 1).
Study flow diagram.
Of those 122 studies, seven studies had third wave CBT arms. Three of these studies were not eligible for inclusion in the current review because they compared third wave CBT approaches with other psychological therapy approaches (Zettle 1984; Zettle 1989; Dimidjian 2004). These studies were assigned to a separate review on third wave CBT therapies versus other psychological therapies for depression (Hunot 2012). The remaining four studies were included in the current review (Pellowe 2006; Gawrysiak 2009; Ekers 2011; Ekkers 2011).
In March 2013 we updated the searches while restricting them to terms relevant to third wave CBTs (CCDANCTR to 01/02/2013). A total of 151 new references were identified. On the basis of the information provided in abstracts, 142 references were found not to be eligible. Three references reported on protocols for ongoing studies that appear to meet the criteria for the third wave CBT reviews (see Ongoing studies section). We read the full text of six studies to assess their eligibility for either of the two third wave CBT reviews in this series. All of the studies compared a third wave CBT with a non‐active control condition. Two studies were assessed as potentially eligible for this review and are awaiting classification.
See Figure 1 for PRISMA flowchart diagram.
Included studies
Study design
The four studies all used a parallel design. Two of the studies were single centre (Pellowe 2006; Gawrysiak 2009), and two were multi‐centre (Ekers 2011; Ekkers 2011).
Sample size
The overall sample size in each of the four studies ranged from 30 participants (Gawrysiak 2009) to 93 participants (Ekkers 2011).
Setting
Two studies were conducted in a non‐medical university setting (Pellowe 2006; Gawrysiak 2009), one was conducted in primary care (Ekers 2011) and one was conducted in an outpatient psychiatric institute (Ekkers 2011).
Two studies were conducted in the USA (Pellowe 2006; Gawrysiak 2009), one was conducted in the Netherlands (Ekkers 2011) and one in the UK (Ekers 2011).
Participants
Gender
The proportion of female participants in the studies ranged from to 62% (Ekers 2011) to 80% (Gawrysiak 2009).
Age
Two studies included young adults based at a university (Pellowe 2006; Gawrysiak 2009), one study included adults over the age of 18 (Ekers 2011) and one study involved adults of 65 years or older, with a mean age of 72.7 years (Ekkers 2011).
Diagnosis
One study used a computerised version of the revised Clinical Interview Schedule (CIS‐R) to make an assessment of depression according to ICD‐10 criteria (Ekers 2011). One study used a clinically established diagnosis of major depressive disorder (MDD), which was agreed for each potential participant through discussion at team meetings (Ekkers 2011). Both of the other studies used a BDI‐II score of 14 or higher (Gawrysiak 2009) or a BDI‐II score of 10‐29 (Pellowe 2006) to identify people with depression.
The baseline severity of depression was reported in each of the four studies, using the Geriatric Depression Scale (Ekkers 2011) and the BDI‐II (Pellowe 2006; Gawrysiak 2009;Ekers 2011).
Intervention
As described previously in the Methods section, it was planned to group third wave CBT approaches into seven categories. Three categories of third wave CBT were examined in the four included studies. Two studies examined forms of extended behavioural activation (Gawrysiak 2009; Ekers 2011), one study examined acceptance and commitment therapy (ACT) (Pellowe 2006) and one study (Ekkers 2011) examined competitive memory training (COMET), a third wave approach targeting rumination and classified for the purposes of this review as 'other'. All of the studies used manuals to guide the intervention.
In two studies, participants received individual therapy (Gawrysiak 2009; Ekers 2011), and in two studies, therapy was provided in a group format of 6 to 8 participants (Ekkers 2011) and in a group format of 2 to 10 participants (Pellowe 2006).
The number of sessions ranged from one 90‐minute session (Gawrysiak 2009) to 12 sessions over a 3‐month period (Ekers 2011). None of the studies conducted follow‐up assessments.
The therapists were mental health nurses (Ekers 2011), registered CBT therapists (Ekkers 2011), doctoral students (Gawrysiak 2009) and advanced clinical psychology graduate students (Pellowe 2006).
Comparisons
Two studies compared a third wave CBT intervention against usual care/treatment as usual, in which participants were followed up by their general practitioner (GP) or primary care mental health worker and were offered interventions deemed appropriate for their condition as per normal practice (Ekers 2011), or in which participants received pharmacotherapy, with or without psychotherapy, or a supportive and structured treatment conducted by specialist nurses (Ekkers 2011). One study used a no treatment condition (Gawrysiak 2009), and one study used a psychological placebo 'supportive therapy' condition, in which therapists facilitated an unstructured group discussion (Pellowe 2006).
Only one study, a single‐session intervention, did not allow naturalistic prescribing of antidepressants (Gawrysiak 2009). In the other three studies, the number of participants prescribed antidepressants on a naturalistic basis ranged from 8% (Pellowe 2006) to 79% of the sample (Ekkers 2011).
Outcomes
Primary outcomes
Three of the studies provided clinical response figures at post‐treatment. All three studies (Gawrysiak 2009; Ekers 2011;Ekkers 2011) used the Jacobson and Truax procedure to calculate reliable change. Ekers 2011 used two additional measures of response (improvement of at least 50%) and remission (score of 10 or less on the BDI‐II).
Dropout rates were reported by all four studies. The intervention by Gawrysiak 2009 was a single session with no dropouts.
Secondary outcomes
Three studies used the BDI‐II to measure continuous change in depression scores (Pellowe 2006; Gawrysiak 2009;Ekers 2011). Ekkers 2011 used the Quick Inventory of Depression Symptoms Self Report (QIDS‐SR) and the Geriatric Depression Scale (GDS).
Other secondary outcome measures used in the four studies were the Work and Social Adjustment Scale (Ekers 2011), the Client Satisfaction Questionnaire (Pellowe 2006; Ekers 2011), the Ruminative Response Scale (Ekkers 2011), the Beck Anxiety Inventory and Multidimensional Scale of Perceived Social Support (Gawrysiak 2009) and the Acceptance and Action Questionnaire and Dysfunctional Attitude Scale (Pellowe 2006).
Excluded studies
A total of 64 studies were excluded from the whole Meta‐Analysis of Psychotherapies (MAP) programme of reviews, based on the searches conducted in June 2010, along with updated searches in April 2011 and February 2012. Five of those studies included a third wave CBT arm, four of which compared third wave CBT against a treatment as usual or non‐active control condition (Hopko 2003a; Bohlmeijer 2011; Reynolds 2011; Snarski 2011). These four studies were excluded because they used an inpatient population (Hopko 2003a), included people with mild to moderate cognitive impairment (Snarski 2011) or included non‐depressed participants (Bohlmeijer 2011; Reynolds 2011).
In addition, three studies (Zettle 1984; Zettle 1989; Dimidjian 2004) were not included in the current review because they compared third wave CBT with another psychological therapy approach. These three studies are included in the HIRED companion third wave CBT review (Hunot 2012).
In the updated search conducted in March 2013 (CCDANCTR to 01/02/2013), four additional studies were excluded because the diagnoses did not fully meet the inclusion criteria of the review programme. The samples in each study consisted of subclinical depression (Kaviani 2012), partial remission (Korrelboom 2012), mixed population (Pinniger 2012) and chronic depression (Folke 2012).
Studies awaiting classification
Two studies are awaiting classification. The study by Azargoon 2010, written in Farsi, compares mindfulness‐based therapy with a control group and is awaiting translation. The study by Armento 2012 compares single‐session extended behavioural activation focused on religious behaviours with a non‐active 'supportive therapy' control.
Ongoing studies
Of three ongoing studies that meet the inclusion criteria for the third wave CBT reviews, one compares a third wave CBT approach with a non‐active treatment control. This study compares the effect of dialectical behaviour therapy with a waiting list control in a sample of participants with major depressive disorder and suicidal ideation (NCT01441258).
Risk of bias in included studies
Allocation
No information was provided on sequence generation across the four studies. Two of the studies conducted the allocation concealment process independent of the research team (Ekers 2011). The other two studies did not report on the methods used for allocating participants to groups.
Blinding
As it is not possible to blind participants and therapists in psychological therapy trials, the studies were all at high risk of performance bias. Each of the four studies used self‐report outcome measures; therefore the risk of detection bias was assessed as high.
Incomplete outcome data
Gawrysiak 2009 examined a single‐session intervention with a 0% dropout. Pellowe 2006 reported a very low dropout rate and provided reasons for dropout. These two studies were assessed as being at low risk of attrition bias. The other two studies had differential dropout rates between experimental and control conditions. One study reported a dropout rate of 50% in the TAU arm (Ekkers 2011), and neither study provided reasons for dropout; therefore both were assessed as being at high risk of attrition bias.
Selective reporting
None of the studies had published a trial protocol; therefore reporting bias across the four studies was assessed as unclear.
Other potential sources of bias
Therapist qualifications
Studies were classified as having low risk of bias only when the therapists were qualified and had received specific training in the relevant psychological therapy approach. These studies either did not meet the criteria in full or failed to describe therapist qualifications/training in sufficient detail to allow an assessment. Therefore, the risk of bias across the four studies was assessed as unclear.
Treatment fidelity
Studies were classified as being at low risk of bias when the therapy session was monitored through audiotapes or videotapes and monitoring was performed against a manual or with the use of a scale. Two of the studies included in the review monitored therapy sessions using audiotapes/independent raters together with a rating scale to assess fidelity (Pellowe 2006; Ekers 2011); they were assessed as being at low risk of bias. One study stated that a sample of sessions was observed by an independent rater but gave no further information (Ekkers 2011). The fourth study required therapists to check off a list of therapy components as they conducted the session; no independent checks were carried out (Gawrysiak 2009), and the study was deemed to be at high risk of bias.
Researcher allegiance/conflict of interest
In three of the four studies, the person responsible for manualising the experimental condition was a member of the research team (Gawrysiak 2009; Ekers 2011;Ekkers 2011). In the study by Pellowe 2006, the supportive therapy condition was designed 'as an attention control group rather than an active treatment such as CBT', thereby implying an allegiance towards the experimental condition. The overall risk of bias across the four studies was assessed as high.
Therapist allegiance/conflict of interest
In the study by Pellowe 2006, the researcher was also the primary therapist, and potential bias towards the active ACT treatment was indicated (see researcher allegiance section above). In the study by Ekers 2011, the therapists had not received primary psychotherapy training and therefore were deemed not to have allegiance to the experimental condition. The other two studies gave insufficient information to permit a decision to be made.
Other potential sources of bias
Insufficient information was provided across the four studies to allow identification of other consistent sources of bias.
See Figure 2 for graphical representation of 'Risk of bias' items. Further information on the individual studies is provided in Characteristics of included studies.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Effects of interventions
See: Summary of findings for the main comparison Third wave CBT versus TAU for depression
Comparison 1. All third wave CBT approaches versus all treatment as usual control conditions
Primary outcomes
1.1 Treatment efficacy: response
Three studies provided data for clinical response rates at post‐treatment (Gawrysiak 2009; Ekers 2011; Ekkers 2011), based on the Jacobson and Truax reliable change index.
A significant difference in clinical response rates favoured third wave CBT compared with TAU conditions (3 studies, 170 participants, RR 0.51, 95% CI 0.27 to 0.95). Substantial statistical heterogeneity was indicated (I2 = 63%; see Analysis 1.1).
The quality of evidence for this outcome measure was very low (see summary of findings Table for the main comparison).
1.2 Treatment acceptability: dropouts for any reason
Dropout rates were obtained for all four studies (224 participants) at post‐treatment. No significant difference in treatment acceptability based on dropout rates was found between third wave CBT approaches and TAU conditions (RR 1.01, 95% CI 0.08 to 12.30). Substantial statistical heterogeneity was indicated (I2 = 86%; see Analysis 1.2).
The quality of evidence for this outcome measure was very low (see summary of findings Table for the main comparison).
Secondary outcomes
1.3 Remission
Two studies provided remission rates at post‐treatment (Ekers 2011; Ekkers 2011). A significant difference in clinical response rates favoured third wave CBT compared with TAU (140 participants, RR 0.77, 95% CI 0.67 to 0.88; see Analysis 1.3).
The quality of evidence for this outcome measure was very low (see summary of findings Table for the main comparison).
1.4 Severity of depression symptoms
All four studies provided means and SDs for depression levels based on the BDI‐II (Pellowe 2006; Gawrysiak 2009; Ekers 2011) or the QIDS‐SR (Ekkers 2011) at post‐treatment. A significant difference in depression levels favoured third wave CBT compared with TAU conditions (211 participants, SMD ‐1.12, 95% CI ‐1.53 to ‐0.71) based on completers' data (Ekers 2011), full dataset (Gawrysiak 2009) and LOCF data (Pellowe 2006; Ekkers 2011). Moderate statistical heterogeneity was indicated (I2 = 44%; see Analysis 1.4).
The quality of evidence for this outcome measure was very low (see summary of findings Table for the main comparison).
1.5 Improvement in overall symptoms
None of the studies reported on this outcome.
1.6 Anxiety symptoms
One study reported on this outcome at post‐treatment using the Beck Anxiety Inventory (BAI) (Gawrysiak 2009). A significant difference in anxiety levels favoured third wave CBT when compared with TAU conditions (30 participants, MD ‐5.50, 95% CI ‐10.01 to ‐0.99).
The quality of evidence for this outcome measure was very low (see summary of findings Table for the main comparison).
1.7 Adverse effects
None of the studies reported on this outcome.
1.8 Social adjustment
One study reported on this outcome at post‐treatment using the Work and Social Adjustment Scale (WSAS) (Ekers 2011). A significant difference in social adjustment levels favoured third wave CBT compared with TAU conditions (38 participants, MD ‐11.56, 95% CI ‐17.89 to ‐5.23).
The quality of evidence for this outcome measure was very low (see summary of findings Table for the main comparison).
1.9 Quality of life
None of the studies reported on this outcome.
1.10 Economic outcomes
None of the studies reported on this outcome.
Comparison 2. Individual third wave CBT approaches versus all treatment as usual control conditions
2.1 Extended BA versus TAU
Two studies compared extended BA with TAU conditions at post‐treatment (Gawrysiak 2009; Ekers 2011).
Primary outcomes
2.1.1 Treatment efficacy: response
No significant difference in clinical response was found between extended BA and TAU conditions (2 studies, 77 participants, RR 0.29, 95% CI 0.05 to 1.56; see Analysis 1.1).
2.1.2 Treatment acceptability: dropouts for any reason
No significant difference in treatment acceptability based on dropout rates was found between extended BA and TAU (2 studies, 77 participants, RR 3.65, 95% CI 0.85 to 15.78; see Analysis 1.2).
2.2 ACT versus TAU
One study compared ACT with TAU conditions at post‐treatment (Pellowe 2006).
Primary outcomes
2.2.1 Treatment efficacy: response
No data were available for this outcome.
2.2.2 Treatment acceptability: dropouts for any reason
No significant different in treatment acceptability based on dropout rates was found at post‐treatment between ACT and TAU (54 participants, RR 3.00, 95% CI 0.13 to 70.53).
2.3 Other third wave CBT approaches versus TAU
One study compared competitive memory training (COMET) with TAU at post‐treatment (Ekkers 2011).
Primary outcomes
2.3.1 Treatment efficacy: response
A significant difference in clinical response rates favoured COMET compared with TAU (93 participants, RR 0.65, 95% CI 0.52 to 0.83).
2.3.2 Treatment acceptability: dropouts for any reason
A significant difference in treatment acceptability based on dropout rates favoured COMET compared with TAU (93 participants, RR 0.15, 95% CI 0.06 to 0.41).
Test for subgroup differences
Treatment efficacy: response
The test for subgroup differences between extended BA, ACT and COMET showed no significant difference between the two approaches when compared with TAU (Chi2 = 0.88, df = 1, P = 0.35).
Treatment acceptability: dropouts for any reason
The test for subgroup differences between extended BA, ACT and COMET showed a significant difference between the three approaches when compared with TAU (Chi2 = 13.90, df = 2, P = 0.001).
Compariosn 3. All third‐wave CBT approaches versus individual control conditions
3.1 All third wave CBT approaches versus TAU/usual care/no treatment
Three studies compared third wave CBT approaches against TAU/usual care/no treatment at post‐treatment (Gawrysiak 2009; Ekers 2011; Ekkers 2011).
3.1.1 Treatment efficacy: response
A significant difference in clinical response rates favoured third wave CBT compared with TAU/usual care/no treatment (3 studies, 170 participants, RR 0.51, 95% CI 0.27 to 0.95). Substantial statistical heterogeneity was indicated (I2 = 63%; see Analysis 1.1).
3.1.2 Treatment acceptability: dropouts for any reason
No significant difference in treatment acceptability based on dropout rates was found between third wave CBT and TAU/usual care/no treatment (3 studies, 170 participants, RR 0.71, 95% CI 0.03 to 16.07). Substantial statistical heterogeneity was indicated (I2 = 92%; see Analysis 2.2).
3.2 All third wave CBT approaches versus psychological placebo
One study compared third wave CBT with psychological placebo at post‐treatment (Pellowe 2006).
3.2.1 Treatment efficacy: response
The study by Pellowe 2006 did not report on this outcome.
3.2.2 Treatment acceptability: dropouts for any reason
No significant difference in treatment acceptability based on dropout rates was found between third wave CBT and psychological placebo (54 participants, RR 3.00, 95% CI 0.13 to 70.53).
Test for subgroup differences
Treatment efficacy: response
Only one subgroup was included in this outcome; therefore a test for subgroup differences could not be conducted.
Treatment acceptability: dropouts for any reason
The test for subgroup differences between TAU/usual care/no treatment and psychological placebo showed no significant difference between the two control conditions compared with third wave CBT.
Subgroup and sensitivity analyses
It was not possible to conduct subgroup or sensitivity analyses because of the small number of studies included in the review.
Summary of findings tables
The results of our analyses expressed in relative and absolute terms, together with ratings of the quality of evidence, are given in summary of findings Table for the main comparison.
Reporting bias
It was not possible to analyse reporting bias because of the small number of studies included in the review.
Discussion
Summary of main results
This review aimed to assess the efficacy and acceptability of third wave CBT based on three planned comparisons: all third wave CBT approaches compared with all treatment as usual control conditions, individual third wave CBT approaches compared with all TAU control conditions, and all third wave CBT approaches compared with individual TAU control conditions (TAU/usual care/no treatment, waiting list, attention placebo and psychological placebo).
Four small studies (224 participants) were included in the review. Little information was provided about the process of allocating participants to groups, and no studies used independent outcome assessors. Evidence suggested researcher allegiance towards the active treatments. Results showed evidence of a difference in favour of third wave CBT compared with TAU for efficacy at post‐treatment (RR of clinical response 0.51, 95% CI 0.27 to 0.95) based on 3 studies involving a total of 170 participants. No evidence indicated a difference between third wave CBT and TAU control conditions for acceptability at post‐treatment based on all 4 studies, involving 224 participants (RR 1.01, 95% CI 0.08 to 12.30). Substantial statistical heterogeneity was indicated in both primary analyses. Analysis of secondary outcomes revealed an effect in favour of third wave CBT approaches compared with TAU conditions for remission (2 studies, 140 participants, RR 0.77, 95% CI 0.67 to 0.88) and for depression levels (4 studies, 211 participants, SMD ‐1.12, 95% CI ‐1.53 to ‐0.71) at post‐treatment. None of the studies conducted follow‐up assessments.
Overall completeness and applicability of evidence
Although every possible effort was made to identify relevant trials, the number of studies currently included in this review is very small. Given the increasing interest in and application of third wave CBT approaches over the past ten years, the possibility that some studies have been missed, either unpublished or in grey literature, cannot be discounted.
When recruiting participants, none of the studies used diagnostic inclusion criteria in a standardised clinical interview to identify potential participants with depression. Whilst it is unclear to what extent many of the participants included in the review met full DSM criteria for major depressive disorder, it could be argued that recruitment of participants based on depression rating scales would be representative of those presenting with depression symptoms in primary care. Nevertheless, it is acknowledged the two trials that used depression rating scales both recruited psychology student samples, and as such could be considered as analogue studies.
Most mindfulness‐based third wave CBT therapies, including FAP, CMT, MBCT, DBT and metacognitive therapy, were not represented at all in the current version of the review. The lack of MBCT studies to date is likely to be explained by the use of this approach as a relapse prevention intervention for people in remission, hence it is beyond the scope of this review. Similarly, the lack of DBT and metacognitive therapy studies may be due to their predominant use in populations with mental health disorders other than depression. A recent search of clinicaltrials.gov conducted by our review team, using the search term 'mindfulness', retrieved more than 300 registered ongoing trials; however, very few of these trials appear to target populations with acute depression.
None of the studies included all of the primary and secondary outcomes of interest in this review, and in particular, none reported on quality of life, adverse effects or economic outcomes. Furthermore, whilst Beck 2012 comments that an essential feature of the efficacy of a psychological therapy approach is its durability over an extended time, no follow‐up assessments were conducted in the four studies included in the review; therefore evidence for the sustained effect of third wave CBT is currently not available.
Quality of the evidence
The quality of evidence for each of our main outcomes was very low (see summary of findings Table for the main comparison). The most common reasons for downgrading across all outcomes were imprecision, indirectness of evidence, inconsistency and risk of bias. All analyses included no more than four studies, three of which had small sample sizes, resulting in wide confidence intervals and lack of statistical power to asses the effects of third wave CBT approaches. The psychological therapies examined in the four studies were limited to three third wave CBT approaches, thus offering a restricted version of the main review question in terms of intervention. Moderate to substantial statistical heterogeneity was observed in all analyses and remained unexplained because of the small number of studies included in the review.
Each of the four studies included in this review described its assignment procedure as 'randomised'; however, none of the studies provided a full account of the sequence generation and allocation concealment methods used. The complete lack of information on these procedures as followed in two studies introduces considerable uncertainty as to whether bias may have been introduced during the allocation process, leading to the decision to assess these risk of bias domains as unclear across studies.
Testing of therapists' fidelity to treatment manuals through systematic or random checking of videotapes/audiotapes against standardised checklists by independent clinicians is a key methodological requirement of psychological therapy studies to provide certainty that any observed treatment effect can be attributed to specific components and characteristics of the model. Two studies were thorough in their consideration of fidelity and applied appropriate criteria (Pellowe 2006; Ekers 2011). The study by Ekkers 2011 used several appropriate methods in measuring fidelity but lacked information on the method used in observing sessions and on how many sessions were assessed. The study by Gawrysiak 2009 relied upon the therapists' own assessment of their treatment fidelity performed by ticking boxes on a form—a method that exposed the study to performance bias. Overall, the extent to which bias was minimised in the delivery of therapy approaches across studies was assessed as unclear.
Another common source of bias in psychological therapy trials involves researcher allegiance, whereby trialists responsible for developing the manuals/protocols under evaluation might be considered to have a vested interest in their superior efficacy over other approaches. Each of the studies included in the review were exposed to this form of bias, as authors were involved in development of the therapy (Ekkers 2011), had developed a variation of an already established treatment (Gawrysiak 2009; Ekers 2011) or expressly favoured the active therapy against a psychological placebo approach (Pellowe 2006). Overall, therefore, the potential for researcher allegiance towards the third wave CBT approaches under evaluation is considered high across the four studies.
Therapist qualifications and experience are regarded as a further potential source of bias in psychological therapy studies, as the risk of unqualified or inadequately trained therapists delivering the intervention without appropriate skill and accuracy is considered high. The therapists used in the four included studies consisted of a diverse group of clinicians in terms of background qualifications, and information provided on their level of experience was inadequate; hence an overall assessment of unclear risk of bias was made.
It is clear that the four studies included in the review were diverse in terms of participant age (ranging from a student to an older population), level of depression severity at baseline, type and duration of third wave CBT under examination and the control comparators used. Therefore, it is not surprising that substantial statistical heterogeneity was observed when the study data were combined. It was not possible to determine causes of heterogeneity among the results because of the small number of studies identified for inclusion. Nevertheless, it was considered worthwhile to combine the data in this first version of the review on the basis that a random‐effects meta‐analysis was used, with due caution recommended in interpreting the results.
Potential biases in the review process
Whilst two of the review authors specialise in CBT (TAF is a diplomate of the Academy of Cognitive Therapy, and VH provides CBT in independent practice), no therapists specialising in other psychological therapy approaches were included in the review team; therefore the possibility of a bias towards CBT cannot be excluded.
Whilst developing the third wave cognitive and behavioural therapies review, we have aimed to be transparent about our management of the third wave therapy classification. We have held regular team meetings to ensure 100% consensus regarding the categorisation of approaches, and when uncertainties continued because of lack of information provided in the articles, we have made contact with the authors to request a fuller description. We acknowledge that considerable debate is likely regarding which CBT approaches should be regarded as 'third wave' in theoretical principle. In the current version of the review, we classified competitive memory training, a newly developed third wave approach, within the 'Other' category to ensure that we adhered fully to our a priori classifications. In future versions of the review, it may be necessary to reconsider our management of the categories based on further development of psychological therapy models and approaches. It is possible too that as the evidence base grows, scope will be increased to allow management of the approaches in separate reviews.
Perhaps the most contentious decision in this review was to categorise the extended version of BA as a third wave CBT approach. We note that this decision contrasted with the approach of previous reviews, in which extended BA was regarded as a form of BT. Whilst acknowledging the common components, we decided that the addition of behavioural strategies for targeting rumination, including 'an emphasis on the function of ruminative thinking and on moving attention away from the content of ruminative thoughts towards direct, immediate experience' (Dimidjian 2004) in extended BA set it apart from earlier BA approaches and placed it more in line with third wave approaches.
One study included in the current review (Pellowe 2006) used a control comparator described as a 'supportive therapy'. Initially this study was allocated to the third wave CBT versus other psychological therapies review as an active humanistic therapy. However after careful discussion by the review team, it was decided that when supportive therapy interventions were regarded as an active treatment by participants but as a control treatment by study investigators, they would be re‐categorised as a 'psychological placebo' for inclusion in the TAU reviews of the MAP programme. Hence, Pellowe 2006 was included in the current review. In future versions of the review, the inclusion of psychological placebo conditions will be examined as a potential source of heterogeneity.
Agreements and disagreements with other studies or reviews
Two previous systematic reviews of third wave CBT approaches have limited their remit to participants in remission from depression who have attended an MBCT course (Coelho 2007) or have not conducted meta‐analyses (Hayes 2004).
The systematic review and meta‐analysis by Ost 2008 included 29 studies that examined five different third wave behavioural therapies (ACT, DBT and FAP, as covered in the current review, together with the cognitive‐behavioural analysis sytem of psychotherapy and integrative behavioural couples therapy) against control conditions and active treatments for a wide range of disorders, including borderline personality disorder, eating disorders, epilepsy and smoking, as well as depression. Effect sizes were calculated for ACT and for DBT compared with waiting list and treatment as usual in a set of separate meta‐analyses across all disorders (Ost 2008), thus precluding the possibility of making any meaningful comparisons with the current review.
Two systematic reviews have examined the efficacy of behavioural activation treatments (Cuijpers 2008; Ekers 2008), but neither attempted to differentiate between the extended BA model developed by Martell 2001 and the 'pure' BT approach originally evaluated in the seminal trial by Jacobson 1996; therefore these findings are not comparable with those of the current review.
A recently published systematic review and network analysis examined the efficacy of seven psychological therapies for individuals with depression (Barth 2013); however, third wave CBT interventions were not managed in a separate category, therefore no comparable findings were reported. It is notable, too, that the authors included Internet‐delivered therapies and those delivered face to face, together with studies of participants whose primary disorder was a medical condition, resulting in a more heterogeneous set of populations and interventions than those included in the current review.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Comparison 1 Third wave CBT versus TAU, Outcome 1 Clinical response at post‐treatment.
Comparison 1 Third wave CBT versus TAU, Outcome 2 Treatment acceptability (dropout) at post‐treatment.
Comparison 1 Third wave CBT versus TAU, Outcome 3 Clinical remission at post‐treatment.
Comparison 1 Third wave CBT versus TAU, Outcome 4 Depression levels at post‐treatment.
Comparison 1 Third wave CBT versus TAU, Outcome 5 Anxiety levels at post‐treatment.
Comparison 1 Third wave CBT versus TAU, Outcome 6 Social adjustment levels at post‐treatment.
Comparison 2 Third wave CBT vs types of control condition, Outcome 1 Clinical response at post‐treatment.
Comparison 2 Third wave CBT vs types of control condition, Outcome 2 Treatment acceptability (dropout) at post‐treatment.
| Third wave CBT versus TAU for depression | ||||||
| Patient or population: depression | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Control | Third wave CBT | |||||
| Clinical non‐response at post‐treatment | Study population | RR 0.51 | 170 | ⊕⊝⊝⊝ | ||
| 800 per 1000 | 408 per 1000 | |||||
| Moderate | ||||||
| 688 per 1000 | 351 per 1000 | |||||
| Treatment acceptability (dropout) at post‐treatment | Study population | RR 1.01 | 224 | ⊕⊝⊝⊝ | ||
| 206 per 1000 | 208 per 1000 | |||||
| Moderate | ||||||
| 42 per 1000 | 42 per 1000 | |||||
| Clinical non‐remission at post‐treatment | Study population | RR 0.77 | 140 | ⊕⊝⊝⊝ | ||
| 953 per 1000 | 734 per 1000 | |||||
| Moderate | ||||||
| 938 per 1000 | 722 per 1000 | |||||
| Depression levels at post‐treatment | Mean depression levels at post‐treatment in the intervention groups were | 211 | ⊕⊝⊝⊝ | SMD ‐1.12 (‐1.53 to ‐0.71) | ||
| Anxiety levels at post‐treatment—behavioural activation vs TAU Beck Anxiety Inventory (BAI) | Mean anxiety levels at post‐treatment—behavioural activation vs tau in the intervention groups was | 30 | ⊕⊝⊝⊝ | |||
| Social adjustment levels at post‐treatment— behavioural activation vs TAU Work and Social Ajustment Scale (WSAS) | Mean social adjustment levels at post‐treatment—behavioural activation vs tau in the intervention groups was | 38 | ⊕⊝⊝⊝ | |||
| *The basis for the assumed risk (eg, the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the risk ratio of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence. | ||||||
| aMethod of sequence generation/allocation concealment unclear. As with all psychological therapy trials, blinding of clinicians/participants was not achievable. The risk of bias was assessed as high for researcher allegiance and as unclear for therapist qualifications. | ||||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Clinical response at post‐treatment Show forest plot | 3 | 170 | Risk Ratio (M‐H, Random, 95% CI) | 0.51 [0.27, 0.95] |
| 1.1 Behavioural activation vs TAU | 2 | 77 | Risk Ratio (M‐H, Random, 95% CI) | 0.29 [0.05, 1.56] |
| 1.2 Others (COMET) vs TAU | 1 | 93 | Risk Ratio (M‐H, Random, 95% CI) | 0.65 [0.52, 0.83] |
| 2 Treatment acceptability (dropout) at post‐treatment Show forest plot | 4 | 224 | Risk Ratio (M‐H, Random, 95% CI) | 1.01 [0.08, 12.30] |
| 2.1 Behavioural activation vs TAU | 2 | 77 | Risk Ratio (M‐H, Random, 95% CI) | 3.65 [0.85, 15.78] |
| 2.2 ACT vs TAU | 1 | 54 | Risk Ratio (M‐H, Random, 95% CI) | 3.0 [0.13, 70.53] |
| 2.3 Others (COMET) vs TAU | 1 | 93 | Risk Ratio (M‐H, Random, 95% CI) | 0.15 [0.06, 0.41] |
| 3 Clinical remission at post‐treatment Show forest plot | 2 | 140 | Risk Ratio (M‐H, Random, 95% CI) | 0.77 [0.67, 0.88] |
| 3.1 Behavioural activation vs TAU | 1 | 47 | Risk Ratio (M‐H, Random, 95% CI) | 0.70 [0.48, 1.00] |
| 3.2 Others (COMET) vs TAU | 1 | 93 | Risk Ratio (M‐H, Random, 95% CI) | 0.78 [0.67, 0.90] |
| 4 Depression levels at post‐treatment Show forest plot | 4 | 211 | Std. Mean Difference (IV, Random, 95% CI) | ‐1.12 [‐1.53, ‐0.71] |
| 4.1 Behavioural activation vs TAU | 2 | 68 | Std. Mean Difference (IV, Random, 95% CI) | ‐1.36 [‐1.90, ‐0.82] |
| 4.2 ACT vs TAU | 1 | 52 | Std. Mean Difference (IV, Random, 95% CI) | ‐0.60 [‐1.16, ‐0.04] |
| 4.3 Others (COMET) vs TAU | 1 | 91 | Std. Mean Difference (IV, Random, 95% CI) | ‐1.27 [‐1.73, ‐0.82] |
| 5 Anxiety levels at post‐treatment Show forest plot | 1 | Mean Difference (IV, Random, 95% CI) | Totals not selected | |
| 5.1 Behavioural activation vs TAU | 1 | Mean Difference (IV, Random, 95% CI) | 0.0 [0.0, 0.0] | |
| 6 Social adjustment levels at post‐treatment Show forest plot | 1 | Mean Difference (IV, Random, 95% CI) | Totals not selected | |
| 6.1 Behavioural activation vs TAU | 1 | Mean Difference (IV, Random, 95% CI) | 0.0 [0.0, 0.0] | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Clinical response at post‐treatment Show forest plot | 3 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 1.1 Third wave CBT vs TAU/usual care/no treatment | 3 | 170 | Risk Ratio (M‐H, Random, 95% CI) | 0.51 [0.27, 0.95] |
| 2 Treatment acceptability (dropout) at post‐treatment Show forest plot | 4 | 224 | Risk Ratio (M‐H, Random, 95% CI) | 1.01 [0.08, 12.30] |
| 2.1 Third wave CBT vs TAU/usual care/no treatment | 3 | 170 | Risk Ratio (M‐H, Random, 95% CI) | 0.71 [0.03, 16.07] |
| 2.2 Third wave CBT vs psychological placebo | 1 | 54 | Risk Ratio (M‐H, Random, 95% CI) | 3.0 [0.13, 70.53] |
