Outcome Variation in the Randomized Trial of Cognitive-Behavioral Therapy Versus Light Therapy for Seasonal Affective Disorder

To the Editor: The authors of the article on treatment of seasonal affective disorder (SAD), published in the September 2015 issue of the Journal (1), conclude that the findings suggest that cognitive-behavioral therapy for SAD and light therapy are comparably effective for SAD. The article did show a lack of difference between treatments but did not analyze for noninferiority. The proportions of study participants in each treatment group who remitted were –14.7 to 15.5, as determined by the Structured Interview Guide for the Hamilton Rating Scale for Depression–SAD Version, and were –22.5 to 7.1, as determined by the Beck Depression Inventory–Second Edition (ranges reflect a 95% CI). These proportions indicate a wide difference in possible outcomes showing that we cannot say the treatments are comparable.