Sex differences in the impact of trauma on alcohol self-administration

Challenging encounters can lead to escalated alcohol consumption, as evidenced by individuals grappling with posttraumatic stress disorder (PTSD). However, the precise influence of prior stress experiences, as opposed to acute stressors, on alcohol intake remains incompletely understood. This study sought to simulate the enduring repercussions of trauma using a stress paradigm involving foot shocks presented in an odor-enriched environment. The presence of a scent throughout contextual fear conditioning is more likely to cause stress effects to generalize across various environments, and this paradigm previously reduced working memory performance, one hallmark of PTSD. Male and female Wistar rats were exposed to the stress or control condition (no foot shock), then trained to perform lever presses to obtain alcohol reinforcement. The findings revealed intriguing disparities between the sexes in past stress effects on the acquisition of alcohol self-administration. Specifically, female rats exhibited divergent patterns of alcohol acquisition across days, with the control group showing a swifter acquisition compared to their previously stressed counterparts. This pattern was not observed in males, nor did either sex show differences in relapse-like self-administration after a 5-week abstinence period. Unexpectedly, presentation of the stress session odor cue did not alter alcohol self-administration behavior. Together, these data support heightened sensitivity of females to a trauma-like stressor, although in rats this decreased self-administration, contrary to human data.