Study shows generational decline in Australia's mental health

It’s widely agreed that young people’s mental health has declined in developed countries in recent years. However, it has been debated whether this is an effect seen just in the post-millennium cohort, as well as whether it is a temporary shift that recovers with age, or a more permanent and worrying trend.

The new study, published today in the journal Proceedings of the National Academy of Sciences (PNAS), sought to answer this question by tracking the mental health of a dedicated cohort of Australians for 20 years from 2001 to 2020.

Drawing on data from the HILDA survey, a nationally representative survey of 9000 households, the researchers assessed how a birth cohort’s mental health changed as they aged and compared the mental health of each cohort (those born in each decade from 1940 to 1990) at the same age.

They found that people born in the 1990s have poorer mental health for their age than any previous generation and do not show the improvements in mental health as they age, as experienced by earlier generations. Importantly, the researchers found that this decline in mental health from around 2010 also impacted those born in the 1980s and, to a lesser extent, even the 1970s.

“Much of the focus to date has been on the declining mental health of school-aged children and adolescents, where we expect their mental health to eventually improve as they enter adulthood. But this study shows this pattern is changing and that it is not just the kids we need to worry about,” said lead author Dr Richard Morris, senior research fellow in the University of Sydney’s Faculty of Medicine and Health.

Professor Nick Glozier says the study findings are very robust—using multiple measures of mental ill-health. However, it does not address the cause of this population-level mental health decline.

“That’s a very difficult question to answer,” said consultant psychiatrist and senior author Professor Nick Glozier, Professor of Psychological Medicine at the University of Sydney. “But what we are looking for is a shared experience that is likely to have impacted all generations or age cohorts at that time, be it in different ways, with young people the most affected.”

Authors from the University of Sydney, University of Melbourne and ANU discuss several local and global challenges that could be impacting this trajectory including the advent and growth of social media, lack of physical activity and poor sleep, climate change and the changing nature of work.

Although likely to reflect megatrends in society, the researchers are unable to account for the possible impact increased community awareness of mental health and less stigma could have on survey results. They also note that the same deterioration in younger generations was not seen for life satisfaction results.

They write: “This study provides a starting point for more in-depth analysis, and we hope it will encourage other researchers to closely examine the changes that have happened in mental ill-health in Australia in the last decade.”

“Understanding the context and changes in society that have differently affected young people may inform efforts to ameliorate this trend and prevent it from continuing for emerging cohorts.”

This paper used data from the Household, Income and Labour Dynamics in Australia Survey (HILDA) conducted by the Australian Government however the views and findings expressed in this paper are those of the authors. The research was supported by the Australian Government through the Australian Research Council’s Centre of Excellence for Children and Families over the Life Course.

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