Substance use predictors of attendance among veterans in integrated PTSD and alcohol use disorder treatment

Comorbid post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) is common, defined by greater severity and impairment than either disorder alone, and associated with poor treatment attendance. Exposure therapies are effective in treating PTSD+AUD, yet substance use is still cited as a potential contraindication for exposure. This study examined substance use-related predictors of session attendance among veterans (N = 119) randomized to receive integrated exposure therapy (Concurrent Treatment of PTSD and Substance Use Disorders using Prolonged Exposure [COPE]; Back et al., 2015) or integrated coping skills therapy (Seeking Safety [SS]; Najavits, 2002) in a clinical trial for comorbid PTSD+AUD (Norman et al., 2019). At baseline, greater percentage of heavy drinking days (β = -0.23, p = .011) and greater AUD severity per structured clinical interview for DSM-IV-TR (β = -0.21, p = .019) predicted fewer sessions across both treatments. Treatment type did not moderate the relationship between predictors and attendance, except for a trend for craving (p = .057), where greater craving predicted fewer sessions in SS (β = -0.31, p = .02) but not COPE (β = 0.14, p = .28). Percentage of abstinence days, AUD duration, and living in a controlled environment (e.g., recovery home) at the start of therapy were not associated with attendance in either treatment condition. Only a subset of substance use characteristics predicted attendance. Findings did not support the notion that alcohol use leads to lower attendance in exposure therapy compared to nonexposure therapy.