Outcomes one and two winters following cognitive-behavioral therapy or light therapy for seasonal affective disorder

Objective: The central public health challenge for winter seasonal affective disorder (SAD) is recurrence prevention. Preliminary studies suggest better long-term outcomes following cognitive-behavioral therapy tailored for SAD (CBT-SAD) than light therapy. The present study is a large, randomized head-to-head comparison of these treatments on outcomes one and two winters after acute treatment. Method: Community adults withmajor depression, recurrent with seasonal pattern (N=177) were followed one and two winters after a randomizedtrial of 6weeks of CBT-SAD(N=88) or light therapy (N=89). Prospective follow-up visits occurred in January or February of each year, and major depression status was assessed by telephone in October and December of the first year. The primary outcome was winter depression recurrence status on the Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorder Version (SIGH-SAD). Other outcomes were depression severity on the SIGH-SAD and the Beck Depression Inventory-Second Edition (BDI-II), remission status based on severity cutoff scores, and major depression status fromtracking calls. Results: The treatments did not differ on any outcome during the first year of follow-up. At the secondwinter, CBT-SADwas associated with a smaller proportionof SIGH-SADrecurrences (27.3% compared with 45.6%), less severe symptoms on both measures, and a larger proportion of remissions defined as a BDI-II score ≤8 (68.3% comparedwith 44.5%) comparedwith light therapy. Nonrecurrence at the next winter was more highly associated with nonrecurrence at the second winter among CBT-SAD participants (relative risk=5.12) compared with light therapy participants (relative risk=1.92). Conclusions: CBT-SAD was superior to light therapy two winters following acute treatment, suggesting greater durability for CBT-SAD.