The mental health of people born in the '90s is not improving with age – unlike other generations, study finds

People born in the 1990s are in poorer mental health than previous generations were at the same age, new research suggests.

So-called '90s babies — which include the youngest millennials and the oldest members of Gen Z — also have not shown improvements in mental health as they have gotten older, a contrast to prior generations, according to a study published Monday.

Researchers at the University of Sydney in Australia tracked the mental health of nearly 30,000 adults from 2001 to 2020. They found mental health declines were particularly apparent in people born in the 1990s and to a lesser extent, people born in the 1980s, which includes the oldest millennials. There was little evidence to suggest that mental health is worsening among people born before the 1980s. 

This suggests that mental health declines among the overall population are being driven by millennials, researchers said.

"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," said lead study author Richard Morris, a senior research fellow at the University of Sydney. "But this study shows this pattern is changing and that it is not just the kids we need to worry about."

Though the latest research comes focused on people in Australia, the U.S. is grappling with its own mental health struggles. Nearly 1 in 5 adults reported having been diagnosed with depression at some point in their lives, according to a report the U.S. Centers for Disease Control and Prevention published in June. Depression was highest among people ages 18 to 24. 

Other research also has found that young adults are more likely than older adults to experience symptoms of anxiety and depression. An analysis of federal data, conducted by KFF, found about 50% of people ages 18 to 24 reported suffering anxiety or depressive symptoms this year. Among adults overall, that figure was about one-third. 

So what's behind the mental health declines of young adults? 

"That's a very difficult question to answer," said Nick Glozier, a psychiatrist and researcher at the University of Sydney. "But what we are looking for is a shared experience that is likely to have impacted all generations ... at that time, be it in different ways, with young people the most affected." 

The KFF researchers pointed to several possible reasons for younger adults having higher rates of mental health conditions: pandemic-related school closures, job and income loss, and remote work. The researchers from the Australian study suggested the growth of social media, declining physical activity levels, poor sleep habits and climate change as factors. 

"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," the authors wrote in the study.