Childhood trauma linked to risky health behaviours through behavioural difficulties, study finds

New research by the University of Bath and the University of São Paulo reveals that childhood trauma can influence risky behaviours in adolescence, driven by externalising behavioural problems, with implications for health interventions worldwide.

Childhood trauma may do more than leave emotional scars: it can also raise the chances that young people will smoke, use drugs or develop unhealthy eating patterns, according to research led by the University of Bath and the University of São Paulo. The study, published in the Journal of Child Psychology and Psychiatry, suggests that behavioural difficulties in adolescence, rather than anxiety or depression alone, are a key part of the pathway from early trauma to later health risks.

The researchers examined data from more than 4,000 participants in the 2004 Pelotas Birth Cohort in Brazil, one of the largest long-running birth studies. By following the same individuals from childhood into late adolescence, the team was able to observe how exposure to potentially traumatic events, mental health problems and health-related behaviour changed over time. That design gives a clearer picture than studies that depend on adults remembering childhood experiences years later.

According to the Bath announcement, the strongest links were seen with externalising problems such as impulsivity, aggression and poor self-control. These difficulties partly accounted for the connection between childhood trauma and later smoking, illicit drug use, problematic alcohol consumption and diets high in ultra-processed foods. By contrast, internalising problems, including anxiety and depression, appeared to play a much smaller role.

Sophie Townend, the study’s lead author at Bath, said interventions that help trauma-exposed young people regulate their emotions and behaviour could do more than ease mental distress. She said they may also reduce behaviours that contribute to cardiovascular disease and other long-term physical problems. Graeme Fairchild, a professor at Bath, said the findings strengthen the case for making effective mental health support more widely available to trauma-exposed youth.

Alicia Matijasevich of the University of São Paulo said the study shows mental health in adolescence may be part of the chain linking early trauma with later health-related behaviour. She said tracking the same participants over time made it possible to see how those experiences connect across different stages of development.

The findings may matter well beyond Brazil. The researchers noted that childhood adversity remains a major public health issue in the UK and across Europe, and they pointed to recent concerns about rising mental health needs among children. One unexpected result was that externalising problems were also linked to higher levels of movement and physical activity, suggesting that not every consequence of trauma is uniformly negative across all health behaviours. Townend said future interventions could try to channel that energy into structured activities such as team sports.

The team now plans to look more closely at whether childhood trauma is also connected to early signs of cardiometabolic disease in late adolescence, including higher resting heart rate, raised blood pressure, increased body weight and unhealthy blood fat levels.