Trauma and the Psychological and Physiological Health of Children and Young People in Low- and Middle-Income Countries upd 02/23

Abstract
Children and young people who experience a traumatic event (e.g., physical or sexual assault, disasters, serious accidents) are vulnerable to developing a range of psychological and psychosocial difficulties in the aftermath, including post-traumatic stress disorder (PTSD). PTSD can be extremely distressing and can significantly influence children's social, educational, and physical health outcomes in the long-term. Research investigating potential PTSD biomarkers has indicated that heart rate (HR) and heart rate variability (HRV; the variation in time intervals between heartbeats) are particularly robust biomarkers of PTSD in adults. However, the limited research with children and young people has yielded mixed results and primarily draws on small samples in high income countries (HIC) where risk of child trauma and subsequent rates of PTSD are relatively low. PTSD in children in low- and middle-income countries (LMIC) has been critically understudied, and HR has not been studied as a PTSD biomarker in such populations, despite high rates of exposure to traumatic events and of mental health disorders, including PTSD. Additionally, longitudinal studies that track HR changes in trauma-exposed children are entirely lacking in the literature despite their ability to provide crucial insight into the link between HR indices and PTSD.

The overall aim of this PhD project is to provide systematic investigation of HR indices as short- and long-term biomarkers of PTSD among children from LMICs, wherein children are at greater risk of exposure to severe and recurrent traumas. Two existing datasets will be utilised to achieve this overarching aim. Firstly, data from 250 trauma-exposed children, aged 8 to 16 years, from Cape Town, South Africa recruited through a prospective ESRC-funded longitudinal study will allow examination of: a) whether HR indices shortly following trauma are predictive of later PTSD; and b) whether physiological changes emerge over time as a consequence of persistent PTSD. Secondly, data from the 2004 Pelotas birth cohort study (n=4231), which recruited all children born in Pelotas, South Brazil in 2004 and has conducted follow-ups at ages 6, 11, 15 and 18 years, will allow examination of: a) whether associations between HR indices and PTSD change during development (e.g., are stronger in adolescence versus childhood); b) whether pre-existing HR/HRV characteristics lead to vulnerability to PTSD given trauma exposure; and c) whether there are cardiac biomarkers that become established in the context of chronic PTSD. Overseas institutional visits to both Stellenbosch University, South Africa and the University of São Paulo, Brazil are planned to facilitate collaboration with co-researchers regarding data collection, analysis, and dissemination of findings.

Potential Applications & Benefits
Children and young people from LMICs comprise the majority of the world's children and are disproportionally likely to be affected by trauma. However, they are profoundly underrepresented in the PTSD evidence base. This project has the potential to make a crucial contribution to our understanding of the psychobiological underpinnings of PTSD among LMIC children. Moreover, the use of longitudinal methods that have yet to be applied in this field will enable novel and important questions to be addressed regarding temporality of associations between trauma, PTSD, and autonomic factors. This project will thus provide major new insights into the psychological and physiological consequences of childhood trauma, a key social determinant of health and wellbeing.