The impact of elevated posttraumatic stress on the efficacy of brief alcohol interventions for heavy drinking college students.

Brief alcohol interventions (BAIs) have been widely adopted for use with college students and are associated with significant reductions in drinking and problems. However, many students do not respond to these approaches and little is known about risk factors for poor response. The current study investigated one possible risk factor by examining the impact of posttraumatic stress (PTS) symptoms on BAI efficacy. This study presents pooled data from two randomized clinical trials that examined the efficacy of counselor-administered BAIs compared with computerized interventions. Participants were 207 college students (53.1% women, 68.1% White/Caucasian, 16.9% with elevated post-traumatic stress) who reported past-month heavy episodic drinking. Follow-up assessments were completed six months post-intervention. Analyses testing differences in frequency of past-month heavy episodic drinking revealed a significant post-traumatic stress by time interaction (F(1,165)=8.27, p=.005) such that individuals screening positive for PTS showed larger reductions in heavy episodic drinking at follow-up. A significant three-way interaction between time, PTS, and intervention condition (F(2,167)=5.76, p=.004) was found for alcohol related consequences. Specifically, among individuals screening positive for PTS, only those that received the counselor-administered BAI showed a significant reduction in consequences at follow-up. These results suggest that overall college students with PTS may respond well to BAIs and that counselor-delivered BAIs may be more efficacious than computer-delivered interventions for reducing alcohol problems for these high-risk students.