Impact of hazardous alcohol use on intensive PTSD treatment outcomes among veterans.

Background: Intensive treatment programmes (ITPs) for posttraumatic stress disorder (PTSD) produce large symptom reductions and have generally higher completion rates compared to traditional weekly care. Although ITPs do not appear to increase substance use, it has yet to be determined whether their effectiveness differs for veterans with and without hazardous alcohol use (HAU). Objective: This study examined the effectiveness of a 3-week Cognitive Processing Therapy-based ITP for 538 veterans with PTSD (66.0% male; mean age = 41.22 years) and with (n = 193) or without HAU (n = 343) for reducing PTSD and depression symptoms. Method: Veterans' PTSD (PCL-5) and depression (PHQ-9) symptoms were assessed at pre-treatment, during treatment, and at post-treatment. HAU (AUDIT-C total score ≥4 for males; ≥3 for females) was measured at intake. Results: Treatment completion rates were high for both individuals who endorsed HAU (92.68%) and those who did not (93.37%), likely due to veterans being housed near the treatment facility. Mixed effects regression models revealed a significant time by alcohol use interaction when predicting both PCL-5 (p < .001) and PHQ-9 (p = .003), suggesting time-trends over the course of the ITP differed based on alcohol use. Veterans who endorsed HAU improved to a statistically significantly lesser extent. However, endpoint differences between groups for both outcomes were small (Cohen's ds between 0.15 and 0.20). Conclusions: Veterans with and without HAU reported significant reductions in PTSD and depression symptoms and completed the ITP at comparably high rates. Findings support the effectiveness of intensive PTSD treatment programmes for individuals with PTSD and HAU. Future studies should utilize controlled designs to evaluate whether intensive PTSD treatment can reduce HAU.