A University of Sydney-led study published today has found 42 percent of Australian adults — more than eight million people — experienced a traumatic event as children. Those affected have a 50 percent higher risk of developing a mental health or substance use disorder than the wider population, the research found. They are more likely to experience anxiety, depression or panic disorder later in life, with more than one in ten projected to attempt suicide.

The findings highlight a need for urgent investment in trauma-informed support to better protect children and prevent lifelong mental health impacts, the authors say.

Led by Dr Lucy Grummitt and Associate Professor Emma Barrett from the Matilda Centre for Research in Mental Health and Substance Use and published in the Australian and New Zealand Journal of Psychiatry, the study found, on average, half of childhood trauma occurred before the age of 10, sometimes occurring in children as young as six. The most common experiences included the unexpected death of a loved one, sexual assault, and witnessing domestic violence, serious injury or death.

“This is a national wake up call,” said Dr Grummitt, Post-doctoral Research Associate at the Matilda Centre. “The scale and lifelong impact of childhood trauma in Australia demands urgent attention from policymakers, service providers and the community.”

Women were more likely to report childhood trauma, the study found, and its true burden may be higher than the results suggest, as the study did not include people experiencing homelessness, incarceration or those living in remote First Nations communities.

The study provides the most recent national estimates of childhood trauma exposure and its long-term health impacts. Researchers assessed 26 types of potentially traumatic events, including abuse, neglect, witnessing domestic violence, sexual assault, serious accidents, natural disasters, illness or injury, exposure to war or conflict and the unexpected death of a loved one. 

It draws on data from 15,893 Australians surveyed in the 2020-2022 National Study of Mental Health and Wellbeing conducted by the Australian Bureau of Statistics. Researchers used this data to examine the prevalence of childhood trauma and its associations with lifetime mental disorders, suicidality (a range of thoughts, behaviours, or actions related to suicide, such as thoughts, ideation and attempts) and physical health conditions. 

“By building on existing research to capture a broader range of traumatic experiences beyond abuse and neglect, our study offers new insights into how early adversity shapes health across our lifetimes,” said Associate Professor Barrett. 

The study also found strong links between childhood trauma and chronic conditions such as asthma, arthritis, cancer and kidney disease. 

“Trauma isn’t just a childhood issue, it can be a lifelong health issue,” said Dr Grummitt. “People generally understand childhood trauma can lead to mental health problems but are less aware of the associations with physical health conditions.”

Unresolved childhood trauma is estimated to cost taxpayers $9.1 billion each year. The researchers said the findings show trauma-informed care must go beyond mental health and substance use services and extend across the entire health system, including hospitals and primary care.

“Trauma-informed care must be embedded in the systems shaping children’s lives,” said Dr Grummitt.

“Two in five children will have experienced a traumatic event by the time they finish school,” she said. “These students are more likely to face suspension or expulsion due to behaviours that result from their trauma. Teachers are on the frontline. They need the tools to recognise when a child’s behaviour signals trauma.

“Children often act out because they’re struggling. Punishing them doesn’t solve the problem; it reinforces feelings of shame and isolation and risks retraumatising them. Responding with care and support can change a child’s life.”