MOOD AND BEHAVIORAL-EFFECTS OF 4-WEEK LIGHT TREATMENT IN WINTER DEPRESSIVES AND CONTROLS

This study investigated (1) the time-course and durability of antidepr essant effects of bright light in winter depressives, and (2) the effe cts of bright light on mood and behavior in normal controls in a 4-wee k open treatment paradigm. Twelve subjects in a major depressive episo de during recurrent major depressive or bipolar disorder with seasonal pattern and 12 control subjects received 2,500 lux light between 0600 and 0800 hours, while 12 controls arose at 0600 hours for quiet activ ities without exposure to bright light. In depressives, maximal decrem ents in depression ratings were not reached until the fourth week Of t reatment. Four depressives experienced clinically significant hypomani c symptoms. Controls treated with light demonstrated significantly hig her clinician ratings of hypomanic symptoms than no-light controls. Wh en depressives and controls were combined. seasonality, but not diagno sis, predicted the emergence of manic-like symptoms. Implications for bright light treatment in the clinical setting are discussed.