CBT, Light Therapy Found Comparable for Seasonal Affective Disorder

Light therapy is a proven method to help alleviate depression in people with seasonal affective disorder (SAD), though almost half of people who use it do not respond, while others—such as those with sensitive eyes—may not be well suited for this therapy.

Cognitive-behavioral therapy (CBT) could be a viable alternative for such people, and a pilot study of a CBT regimen adapted for SAD (CBT-SAD) showed that the treatment has promise (Psychiatric News, December 18, 2009).

A new study published April 10 in AJP in Advance has now validated this early work, finding that CBT-SAD was equally effective as light therapy for alleviating depression associated with SAD.

Kelly Rohan, Ph.D., a professor of psychology at the University of Vermont, developed the CBT program for SAD, which frames the therapy to focus heavily on winter-specific thoughts like cold or darkness.

Participating in the study were 177 adults with an episode of SAD-associated major depression. They were randomly divided to receive either six weeks of CBT-SAD (two 90-minute group sessions a week) or light therapy (30-minute sessions of cool-white fluorescent light each morning). The research team used two methods to measure depression severity: the Structured Interview Guide for the Hamilton Rating Scale for Depression–SAD Version (SIGH-SAD) and Beck Depression Inventory–Second Edition (BDI-II).

To add more real-world applicability to this clinical study, the team employed community therapists to lead the CBT sessions and included participants who had other psychological disorders or were taking antidepressants.

Both treatments produced a significant and comparable reduction in depression severity and were in line with the previous pilot study. At the end of the six weeks, about 47 percent of the subjects in each therapy arm had a remission of their depression based on SIGH-SAD ratings or a 60 percent remission rate based on BDI-II ratings.

“Almost all the people who entered the study had a strong preference to receive light therapy, so the CBT was a bit of a hard sell,” Rohan told Psychiatric News. She added that as a result of that initial preference, the CBT study arm experienced more dropouts (15 compared to one). “But to see that we encountered equal success with each treatment is very encouraging.”

Her group has also just recently completed a longer follow-up of their study subjects, tracking them for two more winters to see how well each treatment prevents the recurrence of symptoms each season. The results of this work will help clinicians and patients decide which therapy to try.

Rohan noted that the study was not meant to challenge whether light therapy is the preferred SAD treatment. “We just wanted to demonstrate that now someone with SAD has proven options.” ■