Geophysical variables and behavior: LVII. Seasonal affective disorder and phototherapy

Seasonal affective disorder, depressive symptoms that recur in fall and winter and abate in spring-summer, for many patients in the United States and Europe, have been alleviated by exposure to bright, full spectrum light for several hours daily (phototherapy). The characteristics of these patients, the procedures used, the theoretical explanations of the mechanisms, and the potential of phototherapy are reviewed.