Seasonal affective disorder in a tropical country: a case report

Seasonality and affective disorders in the Southern Hemisphere were investigated in populations living in latitudes (40 degrees S) equivalent to those of the studies conducted in the Northern Hemisphere. The authors describe a patient with bipolar II affective disorder who was living in a low-latitude area (São Paulo, latitude: 23 degrees 39' S). The patient experienced five episodes of affective disorder that began in the summer and were characterized by symptoms typical of an autumn-winter depression. During the last two depressive episodes, the symptoms remitted after a 4-week course of evening light therapy. The case calls attention to the possibility that seasonality may influence the natural history of affective disorders even in lower latitude regions.