Cocaine and Cognition: A Systematic Quantitative Review

Background: Cocaine use disorder is associated with cognitive deficits. However, the literature remains somewhat ambiguous with respect to which distinct cognitive functions are the most impaired in cocaine use disorder and to how duration of abstinence affects cognitive recovery. Here, we performed a meta-analysis to determine the cognitive domains impaired in cocaine abuse/dependence and the duration of abstinence necessary to achieve cognitive recovery. Methods: A literature search yielded 46 studies that assessed cognitive dysfunction in subjects with cocaine abuse/dependence. Effect-size estimates were calculated using the Comprehensive Meta-Analysis V2, for the following 11 cognitive domains: attention, executive functions, impulsivity, speed of processing, verbal fluency/language, verbal learning and memory, visual learning and memory, visuospatial abilities, and working memory. Within these 11 domains, effect-size estimates were calculated on the basis of abstinence duration: short- (positive for drugs urine screening), intermediate- (<= 12 weeks), and long-term (>= 20 weeks) abstinence. Results: Findings revealed moderate impairment across 8 cognitive domains during intermediate abstinence. The most impaired domains were attention, impulsivity, verbal learning/memory, and working memory. For some domains (attention, speed of processing, and verbal learning/memory), impairments were smaller during short-term abstinence than during intermediate abstinence. Finally, small effect-size estimates were found for long-term abstinence. Discussion: These results suggest significant impairment across multiple cognitive domains in cocaine abusers, and that some of these deficits may be partially masked by the residual or acute withdrawal effects of cocaine. Cognitive dysfunctions remain stable during the first months of abstinence and may abate after 5 months of sobriety.