Internal circadian rhythms drive behaviors in people, animals, and plants. Light and other external time markers shift the rhythms to advance or delay the phase of the internal clock.5 Seasonal affective disorder and other forms of non-seasonal depression may be associated with phase delays. Properly timed light therapy at the end of the night will suppress melatonin secretion and correct the phase delay to reduce depressive symptoms. Light therapy is efficacious for seasonal affective disorder as well as nonseasonal depression.6 Light therapy has been studied for antepartum depression in open-label and small randomized clinical trials.7,8 Corral et al.9 described antidepressant effects of bright light therapy in two women with postpartum depression.