Menstrual cycle phase affects alcohol impairment of working memory.

BACKGROUND

Behavioral endocrinology studies in women suggest that higher circulating levels of the ovarian sex hormone estradiol (E2) may be linked to better working memory performance, especially under conditions of cognitive impairment (e.g., age-related cognitive decline). Phases of the menstrual cycle characterized by different levels of E2 may therefore influence the degree to which women are vulnerable to the acute impairing effect of alcohol on working memory.

METHODS

This study used a within-subjects design to test the hypothesis that women are less sensitive to acute alcohol-induced impairment of working memory during the late follicular phase of the menstrual cycle (when E2 is elevated) compared to the early follicular phase (when E2 is low). A sample of 75 premenopausal women completed two placebo-controlled alcohol administration sessions during the early and late follicular phases, respectively. At both sessions, participants completed an N-Back visual letter task of working memory first following placebo, then again 60 min after consuming a controlled dose of 0.6 g/kg alcohol.

RESULTS

Working memory performance was impaired under alcohol relative to placebo at both the early and late follicular phases of the menstrual cycle. However, as predicted, the magnitude of this impairment was significantly less pronounced during the late versus early follicular phases.

CONCLUSIONS

Women are less vulnerable to the acute impairing effect of alcohol at the late follicular phase of the menstrual cycle when ovulation occurs, possibly as a function of heightened levels of circulating E2. Considered in the context of the broader literature, these findings provide novel evidence to suggest that specific phases of the menstrual cycle may differentially affect women's sensitivity to the acute effects of alcohol on particular cognitive functions.