(139) Investigating Mediators Between Antecedent Childhood Trauma and Drug Overdose Among Adults

Background & Introduction: Antecedent childhood trauma has been positively linked to drug overdose risk but the mediating behavioral, social, and structural factors have yet to be fully illuminated. In this longitudinal study, we tested whether established risk factors for overdose—including daily alcohol use, binge drug use, sex work, incarceration, and inability to access needed health/social services—mediate the relationship between childhood trauma and non-fatal overdose among people who use drugs (PWUD) in Vancouver, Canada. Understanding these pathways is critical for developing targeted interventions to reduce rates of overdose death among trauma-exposed individuals.

Methods: We analyzed data from participants in three community-recruited cohorts of PWUD in Vancouver, Canada, who completed biannual semi-structured interviews between April, 2005 and May, 2025. Childhood trauma was measured using the Childhood Trauma Questionnaire (CTQ). Adjusted logistic regression models with generalized estimating equations examined longitudinal associations between total CTQ score and experiencing a non-fatal overdose in the previous six months. Causal mediation models evaluated five potential mediators: alcohol use, binge drug use, sex work, incarceration, and inability to access needed health/social services. Models were adjusted for age, sex, ethnicity/ancestry, and education. We computed total effects, natural direct effects, natural indirect effects, and percent mediated for each pathway.

Results: Among 4,179 participants (median age 30.9 years; 65.6% male) contributing 47,347 observations, the median CTQ score was 59.0 (IQR: 46.0-76.0), with 47.7% having experienced moderate-to-severe childhood trauma in childhood. Each 10-point increase in CTQ score was associated with increased overdose risk (Adjusted Odds Ratio [AOR]=1.07, 95% CI: 1.04-1.10). Mediation analyses identified three significant pathways: inability to access needed health/social services accounted for 14.7% of the CTQ-overdose association (p < 0.001); binge drug use accounted for 8.6% of the association (p=0.006); and sex work accounted for 4.5% of the association (p=0.042). Daily alcohol use and incarceration showed no significant mediation effects.

Conclusion & Discussion: In this sample of PWUD, behavioral (binge drug use) and social/structural (sex work, healthcare access barriers) pathways mediated the association between childhood trauma and non-fatal overdose risk. Inability to access health or social services emerged as the strongest mediator, underscoring critical gaps in care for PWUD. Public health strategies should also prioritize trauma-informed services for people engaged in sex work and those with binge drug use patterns to reduce overdose risk.

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