Cohort trends in youth suicide in Australia 1964-1997

OBJECTIVE: This paper examines trends in the rate of suicide among young Australians aged 15-24 years from 1964 to 1997 and presents an age-period-cohort analysis of these trends. METHOD: Study design consisted of an age-period-cohort analysis of suicide mortality in Australian youth aged between 15 and 24 for the years 1964-1997 inclusive. Data sources were Australian Bureau of Statistics data on: numbers of deaths due to suicide by gender and age at death; and population at risk in each of eight birth cohorts (1940-1944, 1945-1949, 1950-1954, 1955-1959, 1960-1964, 1965-1969, 1970-1974, and 1975-1979). Main outcome measures were population rates of deaths among males and females in each birth cohort attributed to suicide in each year 1964-1997. RESULTS: The rate of suicide deaths among Australian males aged 15-24 years increased from 8.7 per 100,000 in 1964 to 30.9 per 100,000 in 1997, with the rate among females changing little over the period, from 5.2 per 100,000 in 1964 to 7.1 per 100,000 in 1997. While the rate of deaths attributed to suicide increased over the birth cohorts, analyses revealed that these increases were largely due to period effects, with suicide twice as likely among those aged 15-24 years in 1985-1997 than between 1964 and 1969. CONCLUSIONS: The rate of youth suicide in Australia has increased since 1964, particularly among males. This increase can largely be attributed to period effects rather than to a cohort effect and has been paralleled by an increased rate of youth suicides internationally and by an increase in other psychosocial problems including psychiatric illness, criminal offending and substance use disorders.