Global impairment of prospective memory following acute alcohol

Rationale Whilst the deleterious effects of alcohol on retrospective remembering have been widely documented, no study has yet objectively determined alcohol’s effects on prospective memory (PM)—remembering to do something in the future. Objectives With this aim, the present study determined the acute effects of alcohol upon PM using a laboratory measure that simulates the PM tasks in everyday life—‘Virtual Week’—both (a) in its standard form with regular, irregular, event-based and time-based PM tasks; and (b) an adapted version which enabled exploration of how future event simulation at encoding impacted upon subsequent PM. Methods Forty healthy volunteers were administered 0.6 g/kg ethanol or a matched placebo in a double-blind fashion and completed the two versions of Virtual Week along with prose recall (to tap retrospective memory) and an executive function task. Results Alcohol acutely produced global impairments across all (regular, irregular, event-based and time-based) PM tasks. It also produced impairments of episodic memory which positively correlated with PM performance of irregular tasks. Future-event simulation tended to enhance PM in the placebo but not in the alcohol group. Conclusions These findings on an objective measure of PM suggest that 4–5 units of alcohol will compromise PM abilities in everyday life.