Study links childhood trauma to increased substance use and unexpected effects on heart rate and blood pressure in adolescents

A new study published in the Journal of Child Psychology and Psychiatry reveals that childhood trauma significantly increases the likelihood of engaging in risky behaviours, including harmful alcohol consumption, smoking and illicit drug use, by the age of 18. The research is led by the University of Bath and the University of São Paulo.

The study analysed data from the 2004 Pelotas Birth Cohort in Brazil, which has tracked over 4,000 children living in southern Brazil from birth to age 18. The results show that childhood trauma is alarmingly common amongst young people living in Brazil and has profound health implications:

• Over 80% of participants had experienced at least one traumatic event, such as serious accidents, abuse, domestic violence, or the loss of a parent by the age of 18.
• 25% of adolescents had encountered three or more traumatic experiences by age 18.
• Exposure to traumatic events was strongly linked to an increased likelihood of substance use among adolescents, such that 37% of all problematic alcohol use, 59% of all smoking, and 28% of all illicit drug use at age 18 was explained by childhood trauma exposure.

The study also uncovered an intriguing connection between trauma and cardiovascular health. While the researchers initially expected trauma to be associated with elevated heart rate and blood pressure, they found the opposite: adolescents who experienced more traumatic events had lower heart rate and lower blood pressure, consistent with better cardiovascular health. These findings were unexpected given well-established links between childhood trauma and increased risk of cardiovascular disease in later life.

Lead researcher Megan Bailey from the University of Bath’s Department of Psychology said:

"These findings suggest that reducing childhood trauma exposure could have a profound impact on reducing rates of substance use and addiction in Brazil. Our findings in relation to cardiovascular health were unexpected, as previous research has consistently shown that childhood trauma exposure increases the risk of developing cardiovascular diseases later in life. More research is needed to fully understand the complex effect of childhood trauma on cardiovascular health across the lifespan.”

Co-author Professor Graeme Fairchild, also from the Department of Psychology, said:

"It is surprising to see lower heart rate and blood pressure being associated with childhood trauma in this study of Brazilian adolescents. One possible explanation for this is that some adolescents with mental health conditions—such as conduct disorder or antisocial behaviour—often have a lower resting heart rate. This could help explain why we observed lower heart rates and blood pressure in those exposed to trauma and engaging in substance use – as we already know that childhood trauma is strongly linked to conduct disorder."

Co-author Professor Sarah Halligan, also from the Department of Psychology, said:

“Given the significant role of childhood trauma in shaping adolescent health outcomes, there is an urgent need for early intervention and prevention strategies. Work is already underway in Pelotas to try to reduce levels of violence at the population level, through the Pelotas Pact for Peace – a city-wide initiative to address the causes and consequences of community violence.” 

Co-author, Professor Alicia Matijasevich from the University of São Paulo, Brazil, said:

"Addressing childhood trauma and providing early support to affected young people could be key in reducing future health problems, including substance use and cardiovascular diseases. This is especially critical in low- and middle-income countries like Brazil or South Africa, where many young people are exposed to trauma and resources for intervention are limited."

This new analysis was supported by a studentship awarded to Megan Bailey by the University of Bath and the South-West Doctoral Training Partnership (ESRC), as well as by projects funded by the Brazilian National Research Council, the Research Support Foundation of the State of São Paulo, the Economic and Social Research Council (ESRC), and UK Research and Innovation (UKRI).

ENDS