The frequency of suicide in individual Danish birth cohorts, 1922-1991.

In recent years many suicidologists have based their epidemiological studies on suicide on theories assuming that people born within the same period of time will follow the same suicidal patterns throughout their lives, and that variations in the annual rate of suicide will, therefore, reflect systematic differences between cohorts. Cohort analysis carried out on Danish data showed, however, that although some differences could be found as to the course of events during the life span of the cohorts and also when the material was adjusted for sex, no significant differences could be found between various birth cohorts in the total rates of suicide. The authors argue that the reason for this is that a cohort effect is only one of three dimensions of an analytical tool, namely, Age-Period-Cohort (APC) analysis, and that the balance between the three effects changes over time.