The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence.
OBJECTIVE
The purpose of this study was to assess the evidence base for the efficacy of light therapy in treating mood disorders.


METHODS
The authors systematically searched PubMed (January 1975 to July 2003) to identify randomized, controlled trials of light therapy for mood disorders that fulfilled predefined criteria. These articles were abstracted, and data were synthesized by disease and intervention category.


RESULTS
Only 13% of the studies met the inclusion criteria. Meta-analyses revealed that a significant reduction in depression symptom severity was associated with bright light treatment (eight studies, having an effect size of 0.84 and 95% confidence interval [CI] of 0.60 to 1.08) and dawn simulation in seasonal affective disorder (five studies; effect size=0.73, 95% CI=0.37 to 1.08) and with bright light treatment in nonseasonal depression (three studies; effect size=0.53, 95% CI=0.18 to 0.89). Bright light as an adjunct to antidepressant pharmacotherapy for nonseasonal depression was not effective (five studies; effect size=-0.01, 95% CI=-0.36 to 0.34).


CONCLUSIONS
Many reports of the efficacy of light therapy are not based on rigorous study designs. This analysis of randomized, controlled trials suggests that bright light treatment and dawn simulation for seasonal affective disorder and bright light for nonseasonal depression are efficacious, with effect sizes equivalent to those in most antidepressant pharmacotherapy trials. Adopting standard approaches to light therapy's specific issues (e.g., defining parameters of active versus placebo conditions) and incorporating rigorous designs (e.g., adequate group sizes, randomized assignment) are necessary to evaluate light therapy for mood disorders.
Golden
Robert N
RN
Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7160, USA. robert_golden@med.unc.edu
Gaynes
Bradley N
BN
Ekstrom
R David
RD
Hamer
Robert M
RM
Jacobsen
Frederick M
FM
Suppes
Trisha
T
Wisner
Katherine L
KL
Nemeroff
Charles B
CB
D000328:Adult; D003866:Depressive Disorder / Q000628:therapy; D006801:Humans; D019964:Mood Disorders / Q000188:drug therapy / Q000628:therapy*; D010789:Phototherapy / Q000379:methods; D010919:Placebos; D011619:Psychotropic Drugs / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic / Q000592:standards / Q000706:statistics & numerical data; D012107:Research Design / Q000592:standards; D016574:Seasonal Affective Disorder / Q000628:therapy; D016896:Treatment Outcome
D010919:Placebos; D011619:Psychotropic Drugs