Bright artificial light and the antidepressant fluoxetine are both effective treatments for the
winter form of seasonal affective disorder (SAD). A head-to-head comparison conducted in four Canadian cities
over three winters is reported in an article in the May issue of The American Journal of Psychiatry (AJP), the
official journal of the American Psychiatric Association (APA).
The findings are presented in the article, “The CAN-SAD Study: Randomized Controlled Trial of the
Effectiveness of Light Therapy and Fluoxetine in Patients With Winter Seasonal Affective Disorder” by
Raymond W. Lam, M.D., and colleagues of the Mood Disorder Centre at Vancouver Coastal Health Research
Institute and the University of British Columbia. The rates of remission were 50 percent and 54 percent of
enrolled patients for bright light and fluoxetine, respectively.
Although light therapy and antidepressants are each more effective than placebo, there have been few direct
comparisons of them. In addition, this study was double-blind—all participants received light and a capsule each
day. One group received low-intensity “placebo” light in addition to fluoxetine. The other group received a
placebo capsule and were exposed to 10,000-lux white fluorescent light for 30 minutes a day. Patients judged to
have serious risk of suicide were excluded from the study.
“This study gives patients with a common, but significantly debilitating mood disorder a choice between two
effective treatments,” said Robert Freedman, M.D., AJP editor-in-chief.
Light therapy showed two advantages over fluoxetine. It worked faster, having a greater effect at one week. It
also produced less agitation and less sleep disturbance. However, the overall dropout rate and the dropout rate
due to side effects did not differ between treatments.
Winter depression is the most common type of seasonal mood disorder. Epidemiological studies show
prevalence rates as high as 2.7 percent in higher latitudes. The symptoms may begin in the fall and include
profound lack of energy, excessive sleeping, and overeating, in addition to depressed mood. Impaired
occupational or social functioning is common.
This study was funded by the Canadian Institutes of Health Research (CIHR) and a CIHR/Wyeth Postdoctoral
Fellowship Award. Light boxes were supplied by Uplift Technologies.
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