Concurrent treatment of posttraumatic stress disorder and alcohol dependence: Predictors and moderators of outcome

The present study examined predictors and moderators of treatment response among 165 adults meeting Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria for comorbid posttraumatic stress disorder (PTSD) and alcohol dependence (AD), who were randomized to 24 weeks of Naltrexone (NAL), NAL and prolonged exposure (PE), pill placebo, or pill placebo and PE. All participants received supportive counseling for alcohol use.

Six domains of predictors or moderators (23 variables) were evaluated using measures of PTSD (Posttraumatic Stress Symptom Scale Interview) and AD (days drinking from the timeline follow-back interview) collected every 4 weeks throughout treatment. Multilevel modeling with the Fournier approach was used to evaluate predictors and moderators of rates of symptom improvement and posttreatment outcomes.

Combat trauma, sexual assault trauma, and higher baseline anxiety sensitivity predicted slower improvement and poorer PTSD outcome. Combat trauma, White race, and higher baseline drinking severity predicted poorer drinking outcome. PTSD severity moderated the efficacy of PE on PTSD outcomes, such that the benefit of PE over no-PE was greater for participants with higher baseline PTSD severity. Baseline depressive severity moderated the efficacy of PE on drinking outcomes, whereby the benefit of PE over no-PE was greater for participants with higher depressive symptoms. NAL effects were most beneficial for those with the longest duration of AD.

These results suggest that concurrent, trauma-focused treatment should be recommended for PTSD-AD patients who present with moderate or severe baseline PTSD and depressive symptoms. Future research should examine the mechanisms underlying poorer outcome among identified subgroups of PTSD-AD patients.