Morning vs evening light treatment of patients with winter depression

Abstract

esis for winter depression, morning light (which causes a circadian phase advance) should be more antidepressant than evening light (which causes a delay). Although no studies have shown evening light to be more antidepressant than morning light, investi-gations have shown either no difference or morning light to be superior. The present study assesses these light-exposure schedules in both crossover and parallel-group comparisons. Methods: Fifty-one patients and 49 matched controls were studied for 6 weeks. After a prebaseline assess-ment and a light/dark and sleep/wake adaptation base-line week, subjects were exposed to bright light at ei-ther 6 to 8 AM or 7 to 9 PM for 2 weeks. After a week of withdrawal from light treatment, they were crossed ove