Age, sex and period estimates of Australia's mental health over the last 17 years.

Decline in mental health was only reported by the youngest and oldest respondents, and was notable only in the last 4-5 years. However, the magnitude of the decline was small and further follow-up will be needed to determine whether this is a trend of substantive declining mental health for these specific age cohorts. In contrast, the more consistent finding is that there has been no substantive change in the level of mental health in Australia over the last 17 years. Analysis of the mental health trajectories of baseline age-cohorts confirmed that age differences are consistent over time.