Over 14 million people in the United States alone suffer from Seasonal Affective Disorder (SAD), a psychological mood disorder characterized by depression recurrent during a specific season, primarily winter. (Source: Wikimedia Commons, Alex Proimos)

While most people enjoy the cheerful “holiday season,” others may find the idea of winter less appealing. Over 14 million people in the United States alone suffer from seasonal affective disorder (SAD), a psychological mood disorder characterized by depression that recurs during a specific season, primarily winter. SAD accounts for approximately 15 percent of all cases of recurrent depression. Conventional light therapy, which involves daily exposure to light boxes, has proven effective in acutely treating SAD induced depression (1). However, a new, long-term study led by University of Vermont professor Kelly Rohan indicates that cognitive-behavioral therapy is more effective than conventional light therapy both in preventing the recurrence of SAD and reducing the severity of symptoms over long periods of time (2).

The researchers conducted this two-year study with 177 subjects that exhibited severe, SAD-associated depression. Participants received either six weeks of light therapy, which consisted of a 30-minute exposure to bright, artificial lights every morning or six weeks of SAD-targeted cognitive-behavioral therapy (CBT) sessions twice a week (1). During the CBT sessions, the subjects learned skills to help them cope with negative feelings or exhibit positive behaviors, such as actively seeking social interactions. Researchers then followed up and assessed the prevalence of seasonal depression in participants of both groups over a period of two years (2). Interestingly, during the study, the researchers also encouraged participants of light therapy to continue using their light boxes the following year, but only 11 percent did (1).

Results showed that the two groups experienced similar relief from SAD-related symptoms during the six-week period, reaffirming light therapy as an effective short-term treatment for SAD. However, CBT participants were much less likely to experience the recurrence of depression and displayed significantly less severe symptoms during the following two years. These results, along with the prevalence of SAD and the inconvenience of daily light therapy over long periods of time, suggest that cognitive-behavioral therapy is a more effective and sustainable long-term treatment than conventional light therapy in treating SAD (1).


  1. University of Vermont. (2015, November 5). In preventing return of winter blues, talk outshines light. ScienceDaily. Retrieved November 8, 2015 from www.sciencedaily.com/releases/2015/11/151105084516.htm
  1. Kelly J. Rohan, Jonah Meyerhoff, Sheau-Yan Ho, Maggie Evans, Teodor T. Postolache, Pamela M. Vacek. Outcomes One and Two Winters Following Cognitive-Behavioral Therapy or Light Therapy for Seasonal Affective Disorder. American Journal of Psychiatry, 2015; appi.ajp.2015.1 DOI: 10.1176/appi.ajp.2015.15060773