CBT vs. Light Therapy for Seasonal Affective Disorder

Bright light therapy can improve winter seasonal affective disorder (SAD), but only in some patients. To examine an alternative treatment, investigators randomized 177 community-recruited, nonsuicidal people with SAD to 6 weeks of a specifically designed cognitive behavioral therapy (CBT) or to daily light therapy per scripted protocol during the same period, both to be completed before spring (women, 84%; mean age, 46). One author developed the CBT program.

About 27% of participants had comorbid axis I diagnoses (largely anxiety disorders); 25% took antidepressant medications. Randomization was stratified by sex, the presence of axis I diagnoses, and current antidepressant medication status. CBT was administered in twice-weekly, 90-minute group sessions. It involved the usual techniques for depression; it also addressed negative thoughts related to darkness and winter weather, employed behavioral activation to schedule pleasant events, and included personalized relapse prevention strategies.

One patient receiving light therapy and 13 receiving CBT dropped out. At 6 weeks, groups showed no clinically meaningful differences. Remission rates were roughly 47% on one depression scale and 56% to 64% on another. In both groups, presence of comorbidities was associated with higher depression scores throughout.