Are trauma memories state-dependent? Intrusive memories following alcohol-involved sexual assault

Background: Sexual assault (SA) frequently occurs under the influence of alcohol, and is often followed by both drinking and posttraumatic stress symptoms, including intrusive memories. Although many theories attempt to explain the co-occurrence of alcohol use and posttraumatic stress, one possibility not yet considered is that SA memories may be more likely to occur when there is an encoding-retrieval match in alcohol intoxication state. Objective: The aim of this study was to examine the potential for intrusive memories of SA to be state-dependent, such that intrusive memories for alcohol-involved SA may be more likely to occur in the context of subsequent alcohol intoxication. Method: Participants were 100 college women (age range = 18 to 24 years; 73% White/Caucasian, 89% heterosexual) with a history of alcohol-involved SA (67%) or other, non-alcohol-involved SA (33%). Participants completed daily questionnaires for 30 days assessing past-day drinking and intrusion symptoms. Results: A random-intercept, negative binomial multilevel model revealed that, after controlling for overall frequency of drinking and perceived threat during SA, women with a history of alcohol-involved SA reported more severe intrusion symptoms on drinking days than on non-drinking days. No such difference in intrusions was observed for women who were not intoxicated at the time of the assault. Conclusions: Findings are consistent with the possibility of state-dependent intrusive memories. Additional research is needed to determine whether alcohol intoxication might serve as a discriminative cue preceding intrusive memories of alcohol-involved SA.