(PS11-C64) Trajectories of Alcohol Use Following Sexual Assault: A Secondary Analysis of Daily Data from a Clinical Trial

Background: It is common for sexual assault (SA) survivors to report elevated alcohol use and posttraumatic stress (PTS) symptoms in the months following SA (Dworkin, 2020). Although prior research has examined trajectories of PTS symptoms soon after SA (Dworkin et al., 2023), trajectories of alcohol use have not been examined. It is important to understand typical changes in survivors’ alcohol use over time to better inform early interventions for both alcohol use and PTS after SA. The goal of the present analysis was to examine trajectories of alcohol use following SA using daily data collected within 12 weeks of SA from survivors in an ongoing clinical trial. We aimed to examine (1) the presence of changes in alcohol use (i.e., likelihood of drinking, alcohol quantity on drinking days, and likelihood of heavy episodic drinking (HED)), (2) rates of change in alcohol use, and (3) the potential moderating effect of PTS symptom severity and time since assault on alcohol use. We hypothesized decreased rates of drinking over time and that we would see smaller decreases among individuals with higher baseline PTS symptom severity.

Method: Participants (N = 41) were female-identifying individuals with a recent SA (< 10 weeks), elevated PTS, and alcohol use enrolled in a larger mHealth intervention trial targeting PTS symptoms and alcohol use. Participants first completed a baseline survey with a measure of PTS symptom severity, then tracked their alcohol use in the study app daily for 21 days; some participants also received coping skills in the app.

Results: We first established there were no differences in daily alcohol use as a function of study condition, so we included all participants in models and included condition as a covariate. We conducted generalized mixed-effects models to test hypotheses. We found that participants were less likely to drink on a given day as time in the monitoring period increased. A linear slope fit the data best for alcohol use, suggesting the rate of decrease in odds of drinking was steady across the monitoring period. In hurdle models predicting alcohol use quantity, baseline PTS severity had a significant effect on number of drinks, wherein people with higher PTS severity pre-monitoring tended to consume more drinks on drinking days during the monitoring period. There was no effect of time in daily monitoring on likelihood of HED, but there was a significant effect of PTS severity, where greater PTS severity was associated with an increased likelihood of HED on a given day.

Conclusions: Overall, the findings indicated that drinking days were less likely as more time passed in the monitoring period. There was no evidence that the average time since assault was associated with alcohol outcomes, suggesting alcohol use may not follow a natural recovery trajectory similar to PTS severity. However, the findings suggest PTS severity may be associated with greater likelihood of risky drinking (number of drinks and HED). Interventions targeting PTS symptoms may also reduce harms associated with drinking.