Directed forgetting of memories in cocaine users.

Memory retrieval requires an effective recruitment of inhibitory control to successfully reject unnecessary memories. The use of cocaine is associated with poor cognitive control processes, but little is known about the impact of chronic and recreational use of cocaine on inhibitory control during intentional forgetting. We studied whether chronic and recreational users of cocaine show impairments on the mechanism responsible for intentional forgetting of memories. Two experiments were carried out on chronic cocaine users in rehabilitation (Experiment 1) and recreational cocaine polydrug users (Experiment 2) performing a directed forgetting (DF) task, an index of memory suppression. Participants were matched for sex, age, and intelligence (Raven's standard progressive matrices) with cocaine-free controls and compared on their performance on a DF procedure. Chronic cocaine users in rehabilitation and recreational cocaine polydrug users, as compared with controls, were not able to intentionally suppress the required information and they did not show a reliable DF effect. The consumption of cocaine appears to alter the control processes implicated in intentional suppression of nonrelevant memories in episodic memory. The use of cocaine, even for recreational purposes, seems to be associated with poor performance in effectively triggering this control mechanism. The inability to suppress interference in declarative memory may have repercussion for daily activities. (PsycINFO Database Record