Light Therapy for Depression, and Other Treatment of Seasonal Affective Disorder: A Systematic Review

Conclusions: The value of therapy with a light box for seasonal affective disorder (SAD or seasonal depression) can be neither confirmed nor dismissed. Thus, although a number of studies have been published since SBU released its “Treatment of Depression” report in 2004, the therapy should still be regarded as experimental. There is no significant difference between placebo and light therapy with regard to the number of patients who improve by at least 50%. The results are contradictory when it comes to the number of patients who experience remission. SBU’s meta-analysis of studies that use light boxes shows that the therapy reduces the severity of depression on a rating scale somewhat more than placebo during the first few weeks but that the effect is temporary (insufficient scientific evidence). The evidence is insufficient to determine the effect of light therapy, whether as monotherapy or as an adjunct to antidepressants, on non-seasonal depression. Although treatment in light therapy rooms is well established in Sweden, no satisfactory, controlled studies have been published on the subject. Thus, there is a great need to conduct such studies with enough participants to draw reliable conclusions. Approximately 100 participants are required to establish whether the therapy is moderately more effective than placebo. The studies should also take health economic aspects into consideration.