Testing Trauma Memory as a Predictor of Post-Traumatic Stress in Children and Adolescents: Evidence from Diverse Global Contexts

: (Alternative Format Thesis)

Abstract

Exposure to trauma during childhood or adolescence can lead to post-traumatic stress disorder (PTSD), which may hinder the child’s development. Children in low- and middle-income countries (LMICs) are more likely to be exposed to trauma and to encounter more severe forms of trauma than children in countries (HICs). Yet, most trauma research has focused on the latter. This thesis aimed to address this imbalance by investigating trauma-related risk factors for PTSD among LMIC children, with a particular focus on trauma memory encoding. The thesis utilised longitudinal data from trauma-exposed children and adolescents from both HIC and LMIC contexts to enhance generalisability.

Based on PTSD theoretical models, one risk factor for PTSD development lies in the memory of the traumatic event; however, mixed results have been found. Study 1 examined the construct validity of established manual and automated methods for trauma-memory feature extraction based on trauma narrative accounts in youth from South Africa and the UK. Results indicated no convergence between narrative-derived features and self-reported memory quality. Moreover, trauma narrative–derived features were not associated with PTSD symptoms, whereas self-reported trauma-memory characteristics showed associations with symptom severity that varied by age group across countries, being stronger among younger children in the UK sample compared to younger children in South Africa. Study 2 used machine learning approaches to test whether trauma narratives could predict PTSD symptom severity across UK and South African samples. Predictive performance based on narrative text alone was close to chance across both advanced language models and benchmark approaches, suggesting the limited utility of decontextualised narratives for symptom prediction. Study 3 explored the relationship among memory characteristics, core PTSD and depression symptoms in children and adolescents exposed to multiple types of trauma using multi-country data. Results indicated that PTSD–depression associations were driven mainly by shared cognitive–affective and somatic symptoms, whereas trauma-memory characteristics formed a distinct cluster with only a few connections to PTSD symptoms. Study 4 investigated whether heart rate and heart rate variability reactivity during trauma recall are cross-sectionally and longitudinally associated with PTSD severity. Results showed that heightened high-frequency heart rate variability during trauma recall was prospectively associated with slower symptom reduction over time; however, no physiological response demonstrated sufficient temporal stability to function as a robust longitudinal vulnerability marker for chronic PTSD in youth.

Collectively, these studies contribute new insights into both methodological and conceptual aspects of PTSD risk in youth, with a particular emphasis on cross-cultural applicability. The findings offer novel evidence of the roles of trauma memory and autonomic reactivity in youth PTSD, while strengthening the evidence base in LMIC contexts, which remain critically underrepresented in PTSD research.

Date of Award	20 May 2026
Original language	English
Awarding Institution	University of Bath
Supervisor	Catherine Hamilton-Giachritsis (Supervisor), Sarah Halligan (Supervisor) & Tamsin Sharp (Supervisor)