PS226. The efficacy of light therapy in the treatment of seasonal affective disorder: A meta-analysis of randomized controlled trials

Abstract

Objective: The aim of this meta-analysis was to assess the efficacy of light therapy for the treatment of seasonal affective disorder in adults in comparison with placebo, meta-analyzing randomized, placebo-controlled trials.

Methods: We systematically searched PubMed, MEDLINE, EMBASE, PsycINFO, CINAHL and the Cochrane Central Register of Controlled Trials (CENTRAL) for literature published from January 1980 to March 2015. The primary outcome was improvement of depressive symptom levels measured by validated psychiatric symptom scales, the secondary outcome was to assess response rates. We performed a subgroup analysis comparing studies with patients free of additional psychotropic medication with trials where bright light was given adjunctive to pre-existing psychopharmacological therapy.

Results: 23 studies finally met our pre-defined inclusion criteria. Bright light therapy (BLT) was superior over placebo with an effect size of Hedges`s g= -0.38 (95% Confidence Intervall (CI): -0.53 to -0.23, p= 0.0001) for the primary outcome (21 studies included) and Mantel Haenszel-Risk Ratio of 1.31, 95% CI=1.01 to 1.69 (p=0.04) favouring active treatment over placebo according to response rates (12 studies included). Trials were patients merely had BLT as active treatment indicated a higher effect size (Hedges`s g= -0.51, 95%CI =-0.70 to -0.32 and p=0.001) than studies with concomitant psychopharmacological treatment (Hedges`s g= -0.18, 95% CI= -0.41 to 0.06, p=0.15).

Conclusion: According to our findings, bright light therapy can be regarded as an effective treatment in seasonal affective disorder compared with placebo conditions.

Key words: light therapy, phototherapy, meta-analysis, seasonal affective disorder