Age, period and cohort effects on suicide rates in Australia, 1919–1999


John Snowdon Clinical Associate Professor, Rozelle Hospital, P.O. Box 1, Rozelle NSW 2039, Australia E-mail:


Objective: To examine age, period and cohort effects on Australian suicide rates.

Method: Male suicide rates for successive 5-year periods between 1919 and 1998, and for 1999 were displayed graphically to examine interactions between age, period and cohort effects.

Results: There has been a pronounced period effect on male suicide rates in all age groups over the last few decades, with lower rates in wartime and peak rates for most cohorts in the 1960s. Peak rates of all adult female 5-year age cohorts occurred in the 1960s or early 1970s.

Conclusion: Most so-called cohort effects appear to be associated with environmental changes that may not be a function of the cohort itself. While much attention has focused on the rising suicide rates in young males in Australia, local media and health authorities have given little emphasis to the high rates found in elderly males.