In a head-to-head comparison, bright light and the antidepressant fluoxetine were equally effective for treating seasonal affective disorder. Each treatment was known to work better than placebo, but a large, extended Canadian study by Lam et al. (p. 805 and featured on the cover) now establishes that the two are equivalent to each other. Over 8 weeks, clinical remission occurred in 50% and 54% of the patients who received light therapy and fluoxetine, respectively, for the winter form of seasonal affective disorder. Light therapy worked for patients even with particularly severe symptoms, and it produced a greater response at 1 week. Agitation, sleep disturbance, and palpitations were less common in patients receiving light therapy, but the total number of side effects did not differ. How light effects the brain is discussed in the Images in Neuroscience on p. 771.