Correlates and predictors of PTSD among people with heroin dependence: Findings from the 18–20-year follow-up of the Australian Treatment Outcomes Study (ATOS)

Introduction

Cross-sectional studies have shown a well-established relationship between post-traumatic stress disorder (PTSD) and substance use disorders, particularly, heroin dependence. The present study examines the prevalence, correlates and predictors of PTSD over the longer term among people with a history of heroin dependence.

Method

This study explored PTSD outcomes at the 18–20-year follow-up of the Australian Treatment Outcomes Study, a prospective longitudinal study of 615 people with heroin dependence recruited from Sydney, Australia in 2001–2002. Structured interviews asked participants about demographic characteristics, drug use history and dependence, mental health and patterns of treatment seeking for heroin dependence. Group comparisons between those with and without PTSD were conducted to identify correlates of PTSD at 18–20-years. Logistic regression with backwards stepwise elimination was conducted to identify baseline predictors of PTSD at 18–20-years follow-up.

Results

Of the 615 people assessed at baseline, 393 provided complete PTSD data at 18–20-year follow-up. Of those, 16% met diagnostic criteria for current PTSD. Individuals with PTSD had increased odds of meeting criteria for cannabis dependence, being in current opiate treatment, experiencing a major depressive episode in the past month and lifetime suicide attempt (ORs range 1.85–4.32). Baseline predictors of PTSD at 18–20-year follow-up included female sex, a history of incarceration and current PTSD diagnosis.

Conclusions

This study showed PTSD remained prevalent among a cohort of people with a history of heroin dependence, and was associated with poorer long-term clinical outcomes across substance use and mental health domains. Additionally, individuals with PTSD demonstrated poorer occupational functioning and greater treatment utilisation. The finding that baseline PTSD diagnosis was a predictor of PTSD at 18–20-years stresses the need to provide effective and immediate evidence-based treatment for those with co-occurring PTSD and heroin dependence.