Multi-center study of seasonal affective disorders in Japan. A preliminary report.

A multi-center study on seasonal affective disorder (SAD) was conducted from the autumn of 1988 to the spring of 1989 with the cooperation of 16 facilities in Japan. Forty-six SAD patients were identified among 1104 respondents to our advertisements in mass media, or patients seen at the outpatient clinics. Essentially similar findings to other previous reports were obtained in terms of onset age of the first episode, duration of episode, high proportion of depression in first-degree relatives and atypical vegetative symptoms. However, a nearly equal sex ratio, together with a high proportion of unipolar depression, is characteristic of the present study. Increased appetite and carbohydrate craving were predominant only in female patients, whereas hypersomnia was prominent in both sexes. Effective response to light therapy was found in 17 SAD patients. However, a controlled study on a large number of patients is required to allow final conclusions on the efficacy of light therapy in Japanese SAD patients.