Season of birth of chronic alcoholics.

Season of birth has been well studied in mental illnesses, such as schizophrenia and affective disorders; however, only a few studies have been done for alcoholism. Recently Modestin et al. (1995) found, in a sample from Switzerland, excess birth of male alcoholics in March to July, compared to the general population. The present study attempted to replicate their finding in two independent Japanese samples which comprised a total of 1,947 men with chronic alcoholism. In our study, no birth rate excess in March to July was observed in either sample, while a non-significant birth rate excess (12%) in August to October was noted. It is concluded that there is no consistent trend in season of birth of alcoholics across countries.