Psychological interventions for co‐occurring depression and substance misuse
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
This review will assess the efficacy of psychological interventions alone or in combination with pharmacotherapy for comorbid depression and substance misuse.
Background
Comorbid diagnoses of anxiety and depression amongst individuals with alcohol and/or drug use disorders are common. Co‐occuring disorders have been linked to poorer clinical and social outcomes, increasing the risk of negative effects upon physical and psychological well being. Depression in particular can lead to greater challenges for individuals engaging with services, a higher potential for treatment non‐compliance and a more severe illness course with higher risk of relapse across both the substance use and depressive disorder. Few clinical trials have been conducted to explore the efficacy of non‐pharmaceutical interventions in this population and results from studies examining the effectiveness of psychological treatments for comorbid anxiety/depressive disorders and substance use disorders have been mixed.
Description of the condition
Epidemiological surveys consistently report high rates of anxiety and depression among individuals with alcohol and/or drug use disorders (ABS 2007; Degenhardt, 2001; Farrell 2001; Grant 2004; Kessler 2003). Indeed, compared with the general population, the United States National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) found that individuals with alcohol or drug dependence were 4 and 9 times more likely to suffer with major depression, respectively than individuals with no substance dependence (Grant 2004). Similarly in Australia, the National Survey of Mental Health and Well‐Being found that individuals with alcohol or cannabis dependence were respectively, 3 and 4.5 times more likely to have a concurrent affective disorder when compared with the general population (Degenhardt, 2001). Affective disorders are characterised by either a dramatic elevation or depression of mood and may be accompanied by psychotic symptoms such as hallucinations or delusions e.g. bipolar disorder and dysthymia. Within treatment settings, rates of comorbid substance use and affective disorders are even higher, with 30 to 50% of patients meeting criteria for concurrent major depression (Baker 2007; Bulkstein 1992; Grella 2001; Lubman 2007; Teesson 2005).
Such high rates of co‐occurring disorders are problematic as they have been linked to treatment non‐compliance, a more severe and chronic illness course and an increased risk of relapse in both mental health and substance use problems, as well as greater social and vocational impairment, higher risk of suicidal behaviour and greater use of health services (ABS 2007; Hasin 2003; Sullivan2005). It is therefore important for future research to identify the most efficacious psychosocial (non‐pharmaceutical) interventions in this population. However, few clinical trials have been conducted, and the results of trials examining the effectiveness of psychological treatments among this population have been mixed.
Comorbid disorders are defined by the presence of both depression and substance misuse according to a current DSM‐IV, ICD‐10 or clinical diagnosis of depression and substance use disorder. Inclusion/exclusion criteria from included studies will be highlighted when there is variability in the way these disorders are defined e.g. where a specific measure or cut‐off score is used on a standardised measure that demonstrates equivalence to DSM‐IV or ICD‐10 diagnostic criteria.
Description of the intervention
Manualised psychological (non‐pharmaceutical) interventions will be included. Psychological interventions are differentiated as theory based approaches such as cognitive behaviour therapy (CBT), motivational interviewing, interpersonal psychotherapy and contingency management used alone or in combination with pharmacotherapy. Psychological interventions of any length, using any mode of delivery and administered in any setting will be included in the review. In studies where participants were receiving combined treatments (psychological + pharmacotherapy), inclusion will be determined by documentation of appropriate methodological controls e.g. medication regimes remaining stable for the duration of the study period.
How the intervention might work
Psychological interventions target the factors which may predispose, precipitate or perpetuate comorbid depression and substance misuse.
Why it is important to do this review
A range of psychological interventions have been used for the treatment of comorbid depression and substance misuse but to date only a Cochrane systematic review has been published on Pharmacological treatment for depression during opioid agonist treatment for opioid dependence (Pani 2010) but no systematic review has been conducted to determine which intervention is most efficacious in the population object of this review
Objectives
This review will assess the efficacy of psychological interventions alone or in combination with pharmacotherapy for comorbid depression and substance misuse.
Methods
Criteria for considering studies for this review
Types of studies
All relevant randomised controlled trials (RCTs) and controlled clinical trials (CCTs).
Types of participants
Studies including individuals with a current depressive disorder with co‐occurring substance use problem according to DSM‐IV, ICD‐10 criteria applied by a clinician, via structured clinical interview or via clinical cut‐offs on a psychometric measure of substance misuse. If possible, those with psychosis, bipolar disorder and intellectual disability will be excluded as these individuals form distinct clinical groups with specific needs.
Types of interventions
Experimental conditions:
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CBT with and without motivational interviewing
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Cognitive therapy
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Behaviour therapy
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Contingency management
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Acceptance and commitment therapy (ACT)
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Dialectical behaviour therapy (DBT)
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Interpersonal psychotherapy
Control conditions:
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No or minimal treatment
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Standard care (defined according to study setting but typically consists of case management)
Types of outcome measures
Primary outcomes
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Depression: changes in symptom severity, presence of DSM‐IV disorder/meeting diagnostic cut‐off as measured by validated instruments and structured clinical interviews e.g. the Structured Clinical Interview for DSM‐IV (SCID‐IV) and the Beck Depression Inventory 2nd Edition (BDI‐II).
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Substance use: changes in frequency, quantity, severity of use, presence of DSM‐IV disorder/meeting diagnostic cut‐off as measured by calendar based methods such as Timeline Follow Back (TLFB) and self‐report instruments such as the Alcohol Use Disorders Identification Test (AUDIT).
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Treatment retention and drop out as measured by number of subjects still in treatment at the end of the study.
Secondary outcomes
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Functioning: changes in social, occupational/educational functioning as measured by changes on outcome measures examining quality of life or daily functioning e.g. changes on Global Assessment of Functioning (GAF) scale, changes in employment and relationship status, attendance at work/school/college and engagement in extra‐curricular activities.
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Anxiety: changes in symptom severity, presence of DSM‐IV disorder/meeting diagnostic cut‐off, as measured by validated instruments and structured clinical interviews e.g. the Structured Clinical Interview for DSM‐IV (SCID‐IV) and the Beck Anxiety Inventory (BAI).
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Global clinical severity of mental health disorders: as measured by changes on standardised instruments such as the Clinical Global Impression Scale (CGI) scale.
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Adverse effects linked to treatments delivered.
Search methods for identification of studies
Electronic searches
Relevant trials will be obtained from the following sources:
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The Cochrane Central Register of Controlled Trials (CENTRAL‐ The Cochrane Library, most recent) which includes the Cochrane Drugs and Alcohol Groups Specialised Register
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PubMed (1966 to present)
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PsycINFO (1966 to present)
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EMBASE (1980 to present)
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CINAHL (1982 to present)
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Google Scholar
Databases will be searched using a strategy incorporating the filter for the identification of RCTs (Higgins 2011) combined with selected MeSH terms and free text terms relating to substance abuse.The search strategy for PubMed is shown in Appendix 1.
We will also search some of the main electronic sources of ongoing trials:
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WHO International Clinical Trials Registry Platform (ICTRP) ‐ http://apps.who.int/trialsearch/
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MetaRegister of Controlled Trials ‐ http://controlled‐trials.com/mrct
Non‐English studies with English abstracts will be assessed for inclusion. Non‐English studies that are considered likely to meet inclusion criteria will be translated when possible.The authors of these studies will be contacted to obtain the relevant information.
Searching other resources
Relevant articles will also be hand searched and those using randomised trial methods, or reporting systematic or meta‐analytic reviews will be included in the review. Grey literature including internal reports and conference proceedings will also be searched to identify unpublished studies and the authors of these studies will be contacted to obtain relevant information.
Data collection and analysis
Selection of studies
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All search results (including records identified from electronic searches and other resources) will be merged into RefMan and duplicate records will be deleted
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The title and abstract of each record will then be independently examined by two reviewers and obviously irrelevant records will be deleted.
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Full text articles of the potentially relevant records will be acquired in full text.
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Multiple reports of the same study will be linked.
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The full‐text report of each record will be examined by two reviewers to determine if they meet eligibility criteria for inclusion in the review.
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The authors of the relevant articles will be contacted If there is important information missing from the selected articles.
In the event of a disagreement by the independent reviewers resolution will follow a step‐wise process. Initially the reviewers will discuss the disagreement to establish whether there has been an error by one of the extractors that can easily be resolved. If the disagreement remained unresolved the next step would be to contact the study authors directly and those issues that persisted would be reported explicitly in the review. At all stages of this processes the presence and resolution of disagreements would be recorded and coding techniques would be used to differentiate consensus data from extracted data across both reviewers.
Data extraction and management
Data extraction will be performed independently by two reviewers using a standardised data collection checklist. Any disagreement about data extraction will be resolved via consultation with a third reviewer.
Assessment of risk of bias in included studies
The risk of bias in the included studies will be determined using the criteria and method indicated in the Cochrane Reviewers Handbook Version 5.0.2. A risk of bias table will be completed to assess the methodological quality of the included studies on the following domains: sequence generation, allocation concealment, blinding, incomplete outcome data and selective outcome reporting.This will be achieved by answering a pre‐specified question about the adequacy of the study in relation to each domain, where a judgement of "Yes" indicates low risk of bias, "No" indicates high risk of bias, and "Unclear" indicates unclear or unknown risk of bias. The risk of bias table will be completed independently by two reviewers and any disagreement will be resolved by discussion between reviewers. The risk of bias will be summarised at the outcome level across domains within each study and across studies for each outcome for the meta‐analysis. For detailed description of the criteria used see Appendix 2
Measures of treatment effect
For dichotomous data the relative risk ratio (RR) and their 95% confidence intervals (CI) will be calculated on an intention‐to‐treat basis, . For continuous data, the weighted mean differences (WMD) will be calculated based l. We will calculate the numbers needed to treat/harm (NNT/NNH) where data were homogeneous.
Unit of analysis issues
If all arms in a multi‐arm trial are to be included in the meta‐analysis and one treatment arm is to be included more than once in some comparisons , then we divided the number of events and the number of participants in that arm by the number of treatment comparisons made. This method avoid the multiple use of participants in the pooled estimate of treatment effect while retaining information from each arm of the trial. It compromises the precision of the pooled estimate slightly.
Dealing with missing data
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Whenever possible, contact the original investigators to request missing data.
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Make explicit the assumptions of any methods used to cope with missing data: for example, that the data are assumed missing at random, or that missing values were assumed to have a particular value such as a poor outcome.
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Perform sensitivity analyses to assess how sensitive results are to reasonable changes in the assumptions that are made ( Higgins 2011).
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Address the potential impact of missing data on the findings of the review in the Discussion section.
Assessment of heterogeneity
The presence of clinical, methodological and statistical heterogeneity between the included studies will be assessed including: the content, length, fidelity and setting of treatments, sample characteristics (level of baseline motivation to change, severity of depression, substance used, inclusion and exclusion criteria), blinding of treatment allocation/completion and follow up rates, length of follow up; the use of varying outcomes and measures. Chi squared analysis will be used to determine if results are compatible with chance alone (setting p < .10).
Assessment of reporting biases
If a meta‐analysis is conducted funnel plots (plots of the effect estimate from each study against the standard error) will be used to assess the potential for bias related to the size of the trials, which could indicate possible publication bias.
Data synthesis
The outcomes from the individual trials will be combined through meta‐analysis where possible (comparability of intervention and outcomes between trials) using a fixed effect model unless there was significant heterogeneity, in which case a random effect model have been used. However, there is expected to be a limited number of included studies and wide heterogeneity between them which will make it difficult to perform a meta‐analysis on the primary outcome variables. Instead the findings of the included studies will be summarised systematically.
Subgroup analysis and investigation of heterogeneity
It would be beneficial to include subgroup analysis for: type of CBT, adults, young people, gender, type of substance used. However, a meta‐analysis is unlikely to be performed due to the wide heterogeneity between studies.
Sensitivity analysis
Sensitivity analysis will be performed in terms of the inclusion/exclusion criteria to determine how robust the findings of the review are.
