INTRODUCTION: Adults in opiate agonist treatment (OAT) often have a background of adverse childhood experiences (ACEs) and are more likely to be exposed to a variety of risks that may trigger post-traumatic stress disorder (PTSD). Summative ACE scores are often used to identify individuals at risk of PTSD and continued substance use. What has not been addressed is whether specific ACE factors are exerting a greater influence on the individual. This study investigated whether specific ACEs predicted PTSD, and current continued substance use among adults in long-term OAT.

METHODS: An analysis of data that were collected at the follow-up stage of a study among 131 adults who attended OAT was conducted. Participants attended one of six OAT settings, covering 45% (n = 890) of clients in a defined area of Dublin, Ireland in 2017. Interviews were conducted with 104 participants, 66 males (63%) and 38 females (37%), with an average age of 43 years (SD = 7.4). The Adverse Childhood Questionnaire (ACQ); PTSD checklist (PCL-5); heroin; tranquilliser; cannabis; alcohol; and cocaine used in the previous 28 days were measured using the quantity used score within the Opiate Treatment Index. Socio-demographics and age of first use of these four substances were also collected. The analysis has focussed on relating ACEs to PTSD, age of first drugs use, and current drug use of the participants.

RESULTS: Bivariate analysis showed that the summative ACQ score was significantly correlated with age of first opiate use (p = 0.004). Multiple regression analysis showed that the summative ACQ score and tranquilliser use predicted higher levels of PTSD (R2 = 0.50). Four specific ACEs predicted 54% of the variance in PTSD, these were feeling unloved (β = 0.328) living with a household member who had a problem with alcohol or used illicit street drugs (β = 0.280); verbal abuse (β = 0.219); and living with a person who had a mental illness (β = 0.197).

CONCLUSIONS: While a summation of all ten ACEs predicted higher levels of PTSD, the factor "feeling unloved" as a child provided the single strongest predictor and may represent an overarching risk of PTSD and continued substance use in later life among adults in treatment for an opiate use disorder.