SUPPRESSION OF MELATONIN SECRETION BY BRIGHT LIGHT IN SEASONAL AFFECTIVE-DISORDER

Eleven patients with winter seasonal affective disorder and 10 healthy controls were exposed to light of 3300 lux for 5 min and for I hour r espectively on consecutive evenings at 22:00 hours during winter and s ummer, In the winter the measurements were undertaken both before and after the treatment with bright light for 2 weeks, In the summer, ther e was no treatment. Melatonin concentration in saliva and subjective s leepiness were measured at 22:00 and 23:00 hours on each test, There w as no significant difference in the suppression of melatonin in respon se to the light tests between the patients and the controls. Exposure to light reduced the level of subjective sleepiness more among the pat ients compared to the control subjects. This reduction was not associa ted with the change in melatonin secretion nor the improvement in depr essive symptoms. (C) 1997 Society of Biological Psychiatry.