The impact of trauma characteristics on post-traumatic stress disorder and substance use disorder outcomes across integrated and substance use treatments

Proponents of complex post-traumatic stress disorder (PTSD) constructs suggest that specific trauma characteristics, such as earlier age of first trauma (trauma age) and higher number of traumas (trauma count), may obstruct PTSD symptom reduction in treatment. PTSD and substance use disorders (SUD) commonly co-occur, but the impact of trauma age and count on PTSD treatment responses in a comorbid PTSD and SUD sample is unclear. Further, no studies have examined the impact of trauma characteristics on SUD treatment outcomes or whether their impact on either PTSD or SUD outcomes varies if PTSD is directly addressed. A secondary analysis of a randomized controlled trial was conducted to examine: (1) whether trauma age and count influence co-morbid PTSD and SUD (PTSD + SUD) responses during and following treatment; and (2) whether these effects differed across an exposure-based, integrated PTSD + SUD treatment (Concurrent Treatment of PTSD and Substance Use Disorders using Prolonged Exposure; COPE) and a SUD-only focused treatment (Relapse Prevention Therapy; RPT). Individuals with PTSD + SUD randomized to COPE (n = 39) or RPT (n = 43) provided weekly measurements of PTSD and SUD. Across COPE and RPT, earlier trauma age predicted reduced SUD improvement (B = -0.01, standard error = 0.00). Trauma count did not predict changes in PTSD or SUD during or following treatment. These findings suggest that excluding individuals from exposure-based, integrated treatments on the basis of trauma characteristics is not empirically supported. However, individuals with earlier trauma ages may require additional or unique clinical attention to improve their SUD outcomes.