Light treatment in seasonal and nonseasonal depression.

Ninety patients with major depressive disorder were classified according to seasonal (n = 68, 50 women) or nonseasonal (n = 22, 17 women) pattern according to DSM-III-R. They were also clinically evaluated and rated before and after morning (0600-0800) or evening (1800-2000) light treatment for 10 days in a room with a luminance of 350 cd/m2 (approximately 1500 lx) at eye level. Mood ratings were performed using both the Comprehensive Psychopathological Rating Scale and the Hamilton Depression Rating Scale. Depressed patients with seasonal pattern improved significantly more than those with a nonseasonal pattern suggesting a specific nonplacebo effect of light treatment in depressed patients with seasonal pattern. There were no significant differences in outcome when light treatment was given in the morning or in the evening, and not between patients with and without atypical symptoms such as carbohydrate craving or increased appetite.