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Cochrane Database of Systematic Reviews

Light therapy for preventing seasonal affective disorder

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Information

DOI:
https://doi.org/10.1002/14651858.CD011269.pub2Copy DOI
Database:
  1. Cochrane Database of Systematic Reviews
Version published:
  1. 08 November 2015see what's new
Type:
  1. Intervention
Stage:
  1. Review
Cochrane Editorial Group:
  1. Cochrane Common Mental Disorders Group

Copyright:
  1. Copyright © 2015 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

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Authors

  • Barbara Nussbaumer

    Correspondence to: Department of Evidence‐based Medicine and Clinical Epidemiology, Danube University Krems, Krems, Austria

    [email protected]

  • Angela Kaminski‐Hartenthaler

    Department of Evidence‐based Medicine and Clinical Epidemiology, Danube University Krems, Krems, Austria

  • Catherine A Forneris

    Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, USA

  • Laura C Morgan

    RTI International, Research Triangle Park, USA

  • Jeffrey H Sonis

    Department of Social Medicine; Department of Family Medicine, University of North Carolina at Chapel Hill, Chapel Hill, USA

  • Bradley N Gaynes

    Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, USA

  • Amy Greenblatt

    RTI International, Research Triangle Park, USA

  • Jörg Wipplinger

    Department of Evidence‐based Medicine and Clinical Epidemiology, Danube University Krems, Krems, Austria

  • Linda J Lux

    RTI International, Research Triangle Park, USA

  • Dietmar Winkler

    Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria

  • Megan G Van Noord

    Department of Evidence‐based Medicine and Clinical Epidemiology, Danube University Krems, Krems, Austria

  • Julia Hofmann

    Department of Evidence‐based Medicine and Clinical Epidemiology, Danube University Krems, Krems, Austria

  • Gerald Gartlehner

    RTI International, Research Triangle Park, USA

    Cochrane Austria, Danube University Krems, Krems, Austria

Contributions of authors

GG and BN drafted and revised the protocol. MvN ran scoping searches. BG, JS, DW and CF provided clinical expertise for the Background section. GG, DW, JS, BG, CF, AG, AK, JW, LL, MvN, LM, and JH reviewed the protocol and provided feedback on individual drafts. JH was responsible for project management.

Sources of support

Internal sources

  • Internal funds of Cochrane Austria, Austria, Other.

External sources

  • No sources of support supplied

Declarations of interest

Barbara Nussbaumer ‐ no conflict of interest

Angela Kaminski‐Hartenthaler ‐ no conflict of interest

Catherine A Forneris ‐ no conflict of interest

Laura C Morgan ‐ no conflict of interest

Jeffrey H Sonis ‐ no conflict of interest

Bradley N Gaynes ‐ no conflict of interest

Amy Greenblatt ‐ no conflict of interest

Jörg Wipplinger ‐ no conflict of interest

Linda J Lux ‐ no conflict of interest

Dietmar Winkler ‐ no conflict of interest

Megan G Van Noord ‐ no conflict of interest

Julia Hofmann ‐ During the course of this review, Julia Hofmann became an employee of AstraZeneca, a pharmaceutical company that does not produce any products relevant for the prevention or treatment of seasonal affective disorder. We would like to point out though, that her current employment is in conflict with the Cochrane Commercial Sponsorship policy. Ms Hofmann will not take part in any future updates of the reviews.

Gerald Gartlehner ‐ no conflict of interest

Acknowledgements

We would like to thank Evelyn Auer for providing administrative support during the course of this study.

CRG Funding Acknowledgement:
The National Institute for Health Research (NIHR) is the largest single funder of the Cochrane Depression, Anxiety and Neurosis Group.

Disclaimer:
Views and opinions expressed herein are those of the review authors and do not necessarily reflect those of NIHR, NHS or the Department of Health.

Version history

Published

Title

Stage

Authors

Version

2019 Mar 18

Light therapy for preventing seasonal affective disorder

Review

Barbara Nussbaumer‐Streit, Catherine A Forneris, Laura C Morgan, Megan G Van Noord, Bradley N Gaynes, Amy Greenblatt, Jörg Wipplinger, Linda J Lux, Dietmar Winkler, Gerald Gartlehner

https://doi.org/10.1002/14651858.CD011269.pub3

2015 Nov 08

Light therapy for preventing seasonal affective disorder

Review

Barbara Nussbaumer, Angela Kaminski‐Hartenthaler, Catherine A Forneris, Laura C Morgan, Jeffrey H Sonis, Bradley N Gaynes, Amy Greenblatt, Jörg Wipplinger, Linda J Lux, Dietmar Winkler, Megan G Van Noord, Julia Hofmann, Gerald Gartlehner

https://doi.org/10.1002/14651858.CD011269.pub2

2014 Sep 02

Light therapy for preventing seasonal affective disorder

Protocol

Barbara Nussbaumer, Angela Kaminski‐Hartenthaler, Catherine A Forneris, Laura C Morgan, Jeffrey H Sonis, Bradley N Gaynes, Amy Greenblatt, Jörg Wipplinger, Linda J Lux, Julia Hofmann, Dietmar Winkler, Megan G Van Noord, Gerald Gartlehner

https://doi.org/10.1002/14651858.CD011269

Differences between protocol and review

In the protocol, we planned to contact the authors of publications to request missing results. As the only included study was published more than 20 years ago, we did not contact the study author.

Keywords

MeSH

Medical Subject Headings Check Words

Adult; Humans;

PICOs

Population
Intervention
Comparison
Outcome

The PICO model is widely used and taught in evidence-based health care as a strategy for formulating questions and search strategies and for characterizing clinical studies or meta-analyses. PICO stands for four different potential components of a clinical question: Patient, Population or Problem; Intervention; Comparison; Outcome.

See more on using PICO in the Cochrane Handbook.

PRISMA flow diagram.
Figures and Tables -
Figure 1

PRISMA flow diagram.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across included studies.
Figures and Tables -
Figure 2

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across included studies.

Risk of bias summary: review authors' judgements about each risk of bias item for the included study.
Figures and Tables -
Figure 3

Risk of bias summary: review authors' judgements about each risk of bias item for the included study.

Comparison 1 Bright light therapy vs no light therapy, Outcome 1 Incidence of SAD (per protocol analysis).
Figures and Tables -
Analysis 1.1

Comparison 1 Bright light therapy vs no light therapy, Outcome 1 Incidence of SAD (per protocol analysis).

Comparison 1 Bright light therapy vs no light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 1.2

Comparison 1 Bright light therapy vs no light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).

Comparison 1 Bright light therapy vs no light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 1.3

Comparison 1 Bright light therapy vs no light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).

Comparison 1 Bright light therapy vs no light therapy, Outcome 4 Incidence of severe SAD (per protocol analysis).
Figures and Tables -
Analysis 1.4

Comparison 1 Bright light therapy vs no light therapy, Outcome 4 Incidence of severe SAD (per protocol analysis).

Comparison 1 Bright light therapy vs no light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 1.5

Comparison 1 Bright light therapy vs no light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).

Comparison 1 Bright light therapy vs no light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 1.6

Comparison 1 Bright light therapy vs no light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).

Comparison 1 Bright light therapy vs no light therapy, Outcome 7 Overall rate of discontinuation.
Figures and Tables -
Analysis 1.7

Comparison 1 Bright light therapy vs no light therapy, Outcome 7 Overall rate of discontinuation.

Comparison 2 Infrared light therapy vs no light therapy, Outcome 1 Incidence of SAD (per protocol analysis).
Figures and Tables -
Analysis 2.1

Comparison 2 Infrared light therapy vs no light therapy, Outcome 1 Incidence of SAD (per protocol analysis).

Comparison 2 Infrared light therapy vs no light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 2.2

Comparison 2 Infrared light therapy vs no light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).

Comparison 2 Infrared light therapy vs no light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 2.3

Comparison 2 Infrared light therapy vs no light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).

Comparison 2 Infrared light therapy vs no light therapy, Outcome 4 Incidence of severe SAD (per protocol analysis).
Figures and Tables -
Analysis 2.4

Comparison 2 Infrared light therapy vs no light therapy, Outcome 4 Incidence of severe SAD (per protocol analysis).

Comparison 2 Infrared light therapy vs no light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 2.5

Comparison 2 Infrared light therapy vs no light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).

Comparison 2 Infrared light therapy vs no light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 2.6

Comparison 2 Infrared light therapy vs no light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).

Comparison 2 Infrared light therapy vs no light therapy, Outcome 7 Overall rate of discontinuation.
Figures and Tables -
Analysis 2.7

Comparison 2 Infrared light therapy vs no light therapy, Outcome 7 Overall rate of discontinuation.

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 1 Incidence of SAD (per protocol analysis).
Figures and Tables -
Analysis 3.1

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 1 Incidence of SAD (per protocol analysis).

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 3.2

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 3.3

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 4 Incidence of severe SAD (per protocol analysis).
Figures and Tables -
Analysis 3.4

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 4 Incidence of severe SAD (per protocol analysis).

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 3.5

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 3.6

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 7 Overall discontinuation.
Figures and Tables -
Analysis 3.7

Comparison 3 Light therapy (bright white and infrared) vs no light therapy, Outcome 7 Overall discontinuation.

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 1 Incidence of SAD (per protocol).
Figures and Tables -
Analysis 4.1

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 1 Incidence of SAD (per protocol).

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 4.2

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 2 Incidence of SAD (ITT, assuming no dropout was depressed).

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 4.3

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 3 Incidence of SAD (ITT, assuming all dropouts were depressed).

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 4 Incidence of severe SAD (per protocol).
Figures and Tables -
Analysis 4.4

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 4 Incidence of severe SAD (per protocol).

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).
Figures and Tables -
Analysis 4.5

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 5 Incidence of severe SAD (ITT, assuming no dropout was depressed).

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).
Figures and Tables -
Analysis 4.6

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 6 Incidence of severe SAD (ITT, assuming all dropouts were depressed).

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 7 Overall discontinuation.
Figures and Tables -
Analysis 4.7

Comparison 4 Bright light therapy vs infrared light therapy, Outcome 7 Overall discontinuation.

Summary of findings for the main comparison. Bright white light therapy compared with no light therapy for prevention of SAD

Bright white light therapy compared with no light therapy for prevention of SAD

Patient or population: All participants were known SAD patients who had been successfully treated with conventional light therapy in previous winters
Settings: This was an outpatient field study. Participants chose when (between 6 am and 9 am) and where they would use the visors
Intervention: bright white light therapy
Comparison: no light therapy

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

Number of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

No light therapy

Light therapy

Incidence of SAD (SIGH‐SAD score ≥ 20)

(follow‐up 26 weeks)

Low

RR 0.64
(0.30 to 1.38)

23
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

300 per 1000

192 per 1000
(90 to 414)

Moderate

500 per 1000

320 per 1000

(150 to 690)

High

600 per 1000

276 per 1000

(210 to 966)

Incidence of severe SAD (SIGH‐SAD‐SR (≥ 40))

(follow‐up 26 weeks)

Study population

RR 0.21
(0.03 to 1.75)

23
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

333 per 1000

70 per 1000
(10 to 583)

Overall discontinuation

(follow‐up 26 weeks)

Study population

RR 2.22
(0.29 to 17.27)

28
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

100 per 1000

222 per 1000
(29 to 1000)

*The basis for the assumed risk (e.g. 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 relative effect of the intervention (and its 95% CI)
CI: Confidence interval; RCT: Randomised controlled trial; RR: Risk ratio; SIGH‐SAD‐SR: Structured Interview Guide for the Hamilton Depression Rating Scale‐Seasonal Affective Disorders self rating version

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate
Very low quality: We are very uncertain about the estimate

aDowngraded 2 steps because of severe risk of bias due to non‐blinding and unclear randomisation process and allocation concealment; no intention‐to‐treat analysis was reported, outcomes were self rated, compliance throughout study duration was not checked and participant characteristics were not reported comprehensively

bDowngraded 1 step because of small sample size (lack of power and random error could have influenced results)

Figures and Tables -
Summary of findings for the main comparison. Bright white light therapy compared with no light therapy for prevention of SAD
Summary of findings 2. Infrared light therapy compared with no light therapy for prevention of SAD

Infrared light therapy compared with no light therapy for prevention of SAD

Patient or population: All participants were known SAD patients who had been successfully treated with conventional light therapy in previous winters
Settings: outpatient field study; participants chose when (between 6 am and 9 am) and where they would use the visors
Intervention: infrared light therapy
Comparison: no light therapy

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

Number of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

No light therapy

Infrared light therapy

Incidence of SAD (SIGH‐SAD score ≥ 20)

(follow‐up 26 weeks)

Low

RR 0.50
(0.21 to 1.17)

24
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

300 per 1000

150 per 1000

(63 to 351)

Moderate

500 per 1000

250 per 1000

(105 to 585)

High

600 per 1000

300 per 1000

(126 to 702)

Incidence of severe SAD (SIGH‐SAD‐SR (≥ 40))

(follow‐up 26 weeks)

Study population

RR 0.20
(0.20 to 1.64)

24
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

333 per 1000

67 per 1000
(67 to 547)

Overall discontinuation

(follow‐up 26 weeks)

Study population

RR 1.67
(0.20 to 13.98)

28
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

100 per 1000

167 per 1000
(20 to 1000)

*The basis for the assumed risk (e.g. 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 relative effect of the intervention (and its 95% CI)
CI: Confidence interval;RCT: Randomised controlled trial; RR: Risk ratio; SIGH‐SAD‐SR: Structured Interview Guide for the Hamilton Depression Rating Scale‐Seasonal Affective Disorders self rating version

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate
Very low quality: We are very uncertain about the estimate

aDowngraded 2 steps because of severe risk of bias due to non‐blinding and unclear randomisation process and allocation concealment; no intention‐to‐treat analysis was reported, outcomes were self rated, compliance throughout study duration was not checked and participant characteristics were not reported comprehensively

bDowngraded 1 step because of small sample size (lack of power and random error could have influenced results)

Figures and Tables -
Summary of findings 2. Infrared light therapy compared with no light therapy for prevention of SAD
Summary of findings 3. Light therapy compared with no light therapy for prevention of SAD

Light therapy (bright white or infrared) compared with no light therapy for prevention of SAD

Patient or population: All participants were known SAD patients who had been successfully treated with conventional light therapy in previous winters
Settings: outpatient field study; participants chose when (between 6 am and 9 am) and where they would use the visors
Intervention: light therapy
Comparison: no light therapy

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

Number of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

No light therapy

Infrared light therapy

Incidence of SAD (SIGH‐SAD score ≥ 20)

(follow‐up 26 weeks)

Low

RR 0.57
(0.30 to 1.10)

38
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

300 per 1000

171per 1000

(90 to 330)

Moderate

500 per 1000

285 per 1000

(150 to 550)

High

600 per 1000

342 per 1000

(180 to 660)

Incidence of severe SAD (SIGH‐SAD‐SR (≥ 40))

(follow‐up 26 weeks)

Study population

RR 0.21
(0.04 to 1.05)

38
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

333 per 1000

70 per 1000
(13 to 350)

Overall discontinuation

(follow‐up 26 weeks)

Study population

RR 1.94
(0.27 to 14.01)

46
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

100 per 1000

194 per 1000
(27 to 1000)

*The basis for the assumed risk (e.g. 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 relative effect of the intervention (and its 95% CI)
CI: Confidence interval;RCT: Randomised controlled trial; RR: Risk ratio; SIGH‐SAD‐SR: Structured Interview Guide for the Hamilton Depression Rating Scale‐Seasonal Affective Disorders self rating version

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate
Very low quality: We are very uncertain about the estimate

aDowngraded 2 steps because of severe risk of bias due to non‐blinding and unclear randomisation process and allocation concealment; no intention‐to‐treat analysis was reported, outcomes were self rated, compliance throughout study duration was not checked and participant characteristics were not reported comprehensively

bDowngraded 1 step because of small sample size (lack of power and random error could have influenced results)

Figures and Tables -
Summary of findings 3. Light therapy compared with no light therapy for prevention of SAD
Summary of findings 4. Bright white light therapy compared with infrared light therapy for prevention of SAD

Bright white light therapy compared with infrared light therapy for prevention of SAD

Patient or population: All participants were known SAD patients who had been successfully treated with conventional light therapy in previous winters
Settings: outpatient field study; participants chose when (between 6 am and 9 am) and where they would use the visors
Intervention: bright white light therapy
Comparison: infrared light therapy

Outcomes

Risk in both groups

Relative effect
(95% CI)

Number of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Risk in this treatment group

Risk in this treatment group

Infrared light therapy

Bright white light therapy

Incidence of SAD (SIGH‐SAD score ≥ 20)

(follow‐up 26 weeks)

Study population

RR 1.29
(0.50 to 3.28)

29
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

333 per 1000

357 per 1000

Incidence of severe SAD (SIGH‐SAD‐SR (≥ 40))

(follow‐up 26 weeks)

Study population

RR 1.07
(0.07 to 15.54)

29
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

67 per 1000

71 per 1000

Overall discontinuation

(follow‐up 26 weeks)

Study population

RR 1.33
(0.35 to 5.13)

36
(1 RCT)

⊕⊝⊝⊝
Very lowa,b

167 per 1000

222 per 1000

CI: Confidence interval; RCT: Randomised controlled trial; RR: Risk ratio, SIGH‐SAD‐SR: Structured Interview Guide for the Hamilton Depression Rating Scale‐Seasonal Affective Disorders self rating version

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate
Very low quality: We are very uncertain about the estimate

aDowngraded 2 steps because of severe risk of bias due to non‐blinding and unclear randomisation process and allocation concealment; no intention‐to‐treat analysis was reported, outcomes were self rated, compliance throughout study duration was not checked and participant characteristics were not reported comprehensively

bDowngraded 1 step because of small sample size (lack of power and random error could have influenced results)

Figures and Tables -
Summary of findings 4. Bright white light therapy compared with infrared light therapy for prevention of SAD
Comparison 1. Bright light therapy vs no light therapy

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Incidence of SAD (per protocol analysis) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

2 Incidence of SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

3 Incidence of SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

4 Incidence of severe SAD (per protocol analysis) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

5 Incidence of severe SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

6 Incidence of severe SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

7 Overall rate of discontinuation Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

Figures and Tables -
Comparison 1. Bright light therapy vs no light therapy
Comparison 2. Infrared light therapy vs no light therapy

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Incidence of SAD (per protocol analysis) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

2 Incidence of SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

3 Incidence of SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

4 Incidence of severe SAD (per protocol analysis) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

5 Incidence of severe SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

6 Incidence of severe SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

7 Overall rate of discontinuation Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

Figures and Tables -
Comparison 2. Infrared light therapy vs no light therapy
Comparison 3. Light therapy (bright white and infrared) vs no light therapy

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Incidence of SAD (per protocol analysis) Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

2 Incidence of SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

3 Incidence of SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

4 Incidence of severe SAD (per protocol analysis) Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

5 Incidence of severe SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

6 Incidence of severe SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

7 Overall discontinuation Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

Figures and Tables -
Comparison 3. Light therapy (bright white and infrared) vs no light therapy
Comparison 4. Bright light therapy vs infrared light therapy

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Incidence of SAD (per protocol) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

2 Incidence of SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

3 Incidence of SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

4 Incidence of severe SAD (per protocol) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

5 Incidence of severe SAD (ITT, assuming no dropout was depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

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6 Incidence of severe SAD (ITT, assuming all dropouts were depressed) Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

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7 Overall discontinuation Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

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Figures and Tables -
Comparison 4. Bright light therapy vs infrared light therapy