Predictors of alcohol and substance use among people with post-traumatic stress disorder (PTSD): findings from the NESARC-III study

Purpose: The self-medication hypothesis suggests people may develop Alcohol Use Disorder (AUD) or Non-Alcohol Substance Use Disorder (NA-SUD) following PTSD as a maladaptive way of coping with PTSD symptoms. Given that an accumulation of trauma experiences and interpersonal trauma increase the likelihood and severity of PTSD, we sought to determine whether the number and type of traumas additionally predict AUD and NA-SUD following PTSD. Methods: We analysed data from 36,309 adult participants in the National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III) study (M = 45.63 years, SD = 17.53, 56.3% female) who were administered semi-structured diagnostic interviews of trauma exposure and PTSD, AUD and NA-SUD symptoms. Results: Individuals with PTSD were more likely to have an AUD or NA-SUD than those without PTSD. Endorsement of a greater number of traumas was associated with greater odds of having PTSD, AUD, or NA-SUD. Experience of interpersonal trauma was related to greater odds of having PTSD and subsequent AUD or NA-SUD than not experiencing interpersonal trauma. Multiple experiences of interpersonal trauma compared to one interpersonal trauma exposure also increased the odds of having PTSD followed by AUD or NA-SUD. Conclusions: Interpersonal trauma and multiple experiences of interpersonal trauma may result in individuals turning to alcohol and substances as a way to alleviate intolerable PTSD symptomology, aligning with the self-medication hypothesis. Our findings highlight the importance of ensuring services and support for interpersonal trauma survivors and for those who have experienced multiple traumas given their increased for unfavourable outcomes.