Cohort analysis of Ontario suicide rates, 1877-1976.

Birth cohort studies of suicide rates in Alberta, the United States and Australia indicate that within each generation, suicide rates increase with age. Such studies argue that cohort-specific suicidal risk, together with present high suicide rates among young people predict even higher rates as these generations grow older. Ontario data from a 100-year period demonstrate that within birth cohorts suicide rates consistently increase with age, peak between ages 50 and 70, then decline. Gradual increases in mean suicide rates result in every birth cohort having higher suicide rates than the preceding cohort at almost every age level. These trends combine to produce a regular birth cohort effect and a steady shift in cross-sectional data to higher rates of suicide among younger age groups. Abrupt increases in suicide rates occurring during the Great Depression had only transient effects on birth cohort and cross-sectional curves. Results provide weak support for the hypothesis of cohort-specific suicidal risk and clarify the factors which produce birth cohort effects.