Winter depression recurrence one year after cognitive-behavioral therapy, light therapy, or combination treatment

The central public health challenge in the management of seasonal affective disorder (SAD) is prevention of depression recurrence each fall/winter season. The need for time-limited treatments with enduring effects is underscored by questionable long-term compliance with clinical practice guidelines recommending daily light therapy during the symptomatic months each year. We previously developed a SAD-tailored group cognitive-behavioral therapy (CBT) and tested its acute efficacy in 2 pilot studies. Here, we report an intent-to-treat (ITT) analysis of outcomes during the subsequent winter season (i.e., approximately 1 year after acute treatment) using participants randomized to CBT, light therapy, and combination treatment across our pilot studies (N=69). We used multiple imputation to estimate next winter outcomes for the 17 individuals who dropped out during treatment, were withdrawn from protocol, or were lost to follow-up. The CBT (7.0%) and combination treatment (5.5%) groups had significantly smaller proportions of winter depression recurrences than the light therapy group (36.7%). CBT alone, but not combination treatment, was also associated with significantly lower interviewer- and patient-rated depression severity at 1 year as compared to light therapy alone. Among completers who provided 1-year data, all statistically significant differences between the CBT and light therapy groups persisted after adjustment for ongoing treatment with light therapy, antidepressants, and psychotherapy. If these findings are replicated, CBT could represent a more effective, practical, and palatable approach to long-term SAD management than light therapy.