Trauma and the psychological and physiological health of children and young people in low- and middle-income countries

: (Alternative Format Thesis)

Abstract

Childhood trauma exposure has been associated with a range of physical and mental health problems throughout the lifespan. However, little research has examined the longitudinal associations between childhood trauma exposure and its correlates among children and adolescents living in low- and middle-income countries (LMICs). Youth living in LMICs are disproportionately underrepresented in the evidence base compared to their high-income country counterparts, despite the fact that a) the majority of the world’s children live in LMICs, b) rates of trauma exposure are higher in LMICs compared to high-income countries, and c) the provision and uptake of healthcare services is more limited in LMICs compared to high-income countries. The aim of the current thesis was to therefore examine the impact of childhood trauma exposure on the health of children and adolescents living in LMICs, focusing particularly on the impact on mental health, health risk behaviours, and autonomic functioning. This thesis used data from two population-based, longitudinal, prospective birth cohorts in Brazil (the 2004 Pelotas Birth Cohort Study) and South Africa (the Drakenstein Child Health Study).

Extending upon previous research conducted in high-income countries and with older children, Study 1 evidenced strong cross-sectional associations between childhood violence exposure and both mental health symptoms and disorders among primary school aged children in South Africa. Four subtypes of violence were examined, and violence occurring within the child’s home (either directly experienced or witnessed) emerged as stronger predictors of child psychopathology compared to violence occurring within the community. However, evidence of a longitudinal effect was more limited, and the overall pattern of findings suggested that more proximal experiences of violence may be substantially more important in the prediction of mental health problems compared to more distal experiences. In the same cohort, Study 2 aimed to examine the impact of childhood violence exposure on autonomic functioning, given that previous research has consistently linked both childhood trauma exposure and changes in autonomic functioning to an increased risk of cardiovascular diseases (CVDs) in later life. Childhood violence exposure was not associated with autonomic function at rest, and there was minimal evidence of an effect on autonomic reactivity to stress (during a trauma recall interview). These findings suggest that the effect of trauma exposure on physiological health may not become apparent until adolescence or adulthood and warrants further longitudinal investigation in large population-based samples. Consistent with a large body of existing cross-sectional evidence conducted in high-income countries, Study 3 observed a transdiagnostic, dose-dependent effect of childhood trauma exposure on mental health disorders among adolescents in Brazil, such that exposure to more traumatic events was associated with greater odds of disorder across multiple diagnostic classes, including anxiety, mood, and conduct-oppositional disorders. Notably, weaker longitudinal findings again suggested the greater importance of more proximal experiences in the prediction of mental health problems. Finally, in the same Brazilian birth cohort, Study 4 evidenced a dose-dependent effect of childhood trauma exposure on adolescent substance use behaviours, and also examined a potential pathway from childhood trauma exposure to CVD risk that operated via adolescent substance use. The study observed some evidence to suggest an indirect effect of childhood trauma exposure on autonomic function that operated via adolescence substance use behaviours.

Collectively, these studies have highlighted the substantial impact of childhood trauma exposure on the mental and physical health of children and adolescents living in LMICs, who have previously been disproportionately underrepresented in the evidence base. These findings reinforce a critical need for prevention, intervention, and treatment strategies to address the substantial global burden of childhood trauma exposure and its correlates. Further research is needed regarding the impact of childhood trauma exposure on cardiovascular health, and longitudinal tracking of childhood trauma exposure, mental health symptoms, risk behaviour engagement, and autonomic functioning from childhood to adulthood would benefit this evidence base.

Date of Award	20 May 2026
Original language	English
Awarding Institution	University of Bath
Supervisor	Sarah Halligan (Supervisor), Graeme Fairchild (Supervisor), Alicia Matjasevich (Supervisor) & Gemma Hammerton (Supervisor)