N-Acetylcysteine for the Treatment of Co-Occurring Posttraumatic Stress Disorder and Alcohol Use Disorder: A Double-Blind, Randomized Controlled Trial.

Objective

Posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) are common co-occurring conditions associated with a more severe clinical profile and poorer treatment outcomes than either disorder alone. To date, no medications have proven efficacious in the treatment of co-occurring PTSD/AUD.

Methods

This randomized, double-blind, placebo-controlled trial examined the efficacy of N-acetylcysteine (NAC; 2,400 mg/day) among individuals (N=182, aged 21-65 years) who met DSM-5 criteria for current PTSD/AUD. Participants were randomized 1:1 to receive 12 weeks of NAC (n=93) or placebo (n=89). All participants received weekly, individual, cognitive behavioral therapy (CBT) for AUD. Follow-up visits occurred at 3-, 6-, and 12-months posttreatment. Primary outcomes included the Clinician Administered PTSD Scale for DSM-5 (CAPS-5), PTSD Checklist for DSM-5 (PCL-5), Timeline Follow-Back (TLFB), and the Obsessive Compulsive Drinking Scale at 12 weeks. The TLFB evaluated the frequency and amount of alcohol consumption. A secondary measure evaluated depression symptoms.

Results

Intent-to-treat analyses showed that participants in both the NAC and placebo groups evidenced significant reductions in the CAPS-5 (B=-0.19, P<.001) and PCL-5 (B=-0.20, P<.001) during treatment, with no significant group differences. Both groups also showed significant reductions in alcohol use (drinks per drinking day [B=-0.02, P<.001], percent heavy drinking days [B=-0.14, P<.001], percent days abstinent [B=0.29, P=.022]) and craving (B=-0.12, P<.001) during treatment, but with no significant group differences. There were no group differences in retention or adverse events.

Conclusions

Although NAC was well tolerated, it was not more effective than placebo in improving symptoms of PTSD or AUD when added to individual CBT for AUD. Trial Registration: ClinicalTrials.gov identifier: NCT02966873.