REVEALED: MENTAL HEALTH PATTERNS IN TEENAGERS

Depression affected 19 per cent of students, while anxiety impacted 26 per cent.

A major Australian study tracking more than 6,000 teenagers has revealed how depression, anxiety and sleep problems develop during the high school years, offering new insight into the factors shaping adolescent wellbeing.

Released by the Black Dog Institute, the research followed students from Year 8 to Year 11 across more than 130 schools, collecting annual data on mental health, sleep, family relationships and school experiences.

Different mental health pathways emerge

The study identified four distinct trajectories of depression and anxiety as teenagers progressed through adolescence.

While around two-thirds of students did not experience significant mental health difficulties, up to one-quarter reported persistently high or worsening symptoms.

Depression affected 19 per cent of students, while anxiety impacted 26 per cent.

Professor Aliza Werner-Seidler said the findings highlight the gradual nature of many mental health challenges.

“Our research shows that while most young people navigate adolescence without significant mental health difficulties, a substantial number experience symptoms that worsen over time. This highlights the need for earlier intervention and more targeted support.”

She said identifying young people earlier could help prevent more severe problems.

“What is concerning is that a significant proportion of young people follow trajectories where symptoms remain high or increase during the high school years.

"If we can identify young people earlier in that trajectory, there is a real opportunity to intervene before symptoms become more severe.”

"Bullying, peer conflict, negative family interactions and adverse childhood experiences were linked to poorer outcomes, with girls and gender-diverse young people more likely to experience higher-risk trajectories.

“These trajectories can in part be shaped by young people’s environments and circumstances, including their experiences at school, with their families and more broadly within their social networks,” Professor Werner-Seidler said.

Sleep is strongly linked to well-being

Sleep emerged as one of the strongest predictors of mental health.

Researchers found that 38 per cent of students experienced persistent or worsening insomnia symptoms, with 11 per cent reporting clinically significant insomnia.

Those students were four times more likely to experience high anxiety and six times more likely to experience high depression symptoms.

Black Dog Institute Senior Research Program Manager and PhD candidate Kate Maston said the findings highlight the need to address sleep problems earlier.

“Sleep is often overlooked in conversations about youth mental health, but our findings show it plays a critical role in mental health and wellbeing. Improving how we identify and treat sleep problems in young people could make a significant difference to mental health outcomes.”

Early life adversity and school belonging matter

More than half of participants reported at least one adverse childhood experience by Year 8, including family conflict or parental separation.

These experiences were linked to higher risks of emotional distress, self-harm and suicidal thoughts.

Professor Werner-Seidler said stronger family support could improve long-term outcomes.

Experiences in early life can shape mental health in profound ways. Supporting families, identifying young people exposed to adversity early, and providing support at this stage can make a significant difference to long-term outcomes.

A strong sense of belonging at school was also linked to better well-being, although around one in four students reported low levels of connectedness.

Opportunities for earlier prevention

Professor Werner-Seidler said adolescence represents a critical window for support.

“Adolescence is a critical period where mental health trajectories begin to take shape. What our findings show is that many of the factors influencing these trajectories are identifiable and, in many cases, modifiable.

“By investing in earlier support for young people, strengthening school and family environments, and ensuring services are available when young people first begin to struggle, we have a real opportunity to change the course of mental health outcomes.”