Suicide in Japan: socioeconomic effects on its secular and seasonal trends.

Changes in male and female suicide death rates for 33 years following the end of World War II in Japan were analyzed. The death rates for men and women decreased during periods of economic prosperity and then increased during the years preceding economic depression; that for men also increased after economic depression. When examined by profile analysis, the seasonal variation was slightly but significantly different in the four time periods (1950-1955, 1955-1967, 1967-1974, and 1974-1982) in both sexes except between the last two periods (p less than .05). We suggest that death by suicide and its seasonal variation in Japan were affected by changes in socioeconomic conditions.