Abstract
BACKGROUND: The noradrenergic system has been implicated in alcohol use disorder (AUD) and posttraumatic stress disorder (PTSD), with adrenergic agents reducing drinking in individuals with AUD and improving sleep disturbances in individuals with PTSD. In a recent clinical trial, prazosin, an α1-adrenergic antagonist, was not superior to placebo in reducing PTSD symptoms, sleep problems, or alcohol consumption in a comorbid population; however, patients in both treatment conditions improved in all symptom domains over the course of treatment. It remains unknown whether alcohol abstinence is related to changes in PTSD symptoms and medication effects in individuals with this comorbidity. METHODS: Veterans with comorbid alcohol dependence and PTSD (n = 96) were randomized to prazosin (16 mg) or placebo in a 12-week outpatient, double-blind clinical trial. In this secondary data analysis, we examined main effects of alcohol abstainer status (abstainer vs. nonabstainer), treatment, and their interaction on changes in PTSD symptoms over time using linear mixed models. RESULTS: There was a main effect of alcohol abstainer status on symptoms of PTSD (p = 0.03), such that nonabstainers had lower total Clinician-Administered PTSD Scale (CAPS) scores than abstainers. There was a significant treatment by alcohol abstainer status interaction (p = 0.01); specifically, among placebo-treated individuals, those who did not abstain from alcohol had lower total CAPS scores compared to alcohol abstainers. Within the prazosin-treated group, abstainers and nonabstainers did not differ on total CAPS scores. Results were similar for the avoidance (p = 0.02), reexperiencing (p = 0.01), and hyperarousal (p = 0.04) subscales, such that placebo-treated nonabstainers had lower CAPS scores overall. CONCLUSIONS: Overall, prazosin treatment was not significantly related to changes in PTSD symptoms over the course of the 12-week clinical trial in a comorbid population. Interestingly, placebo-treated alcohol nonabstainers had a significant reduction in PTSD symptoms. Whether placebo-treated individuals continued to use alcohol because of ongoing symptoms of PTSD is not known.