Effects of Cannabis on Neurocognitive Functioning: Recent Advances, Neurodevelopmental Influences, and Sex Differences

Abstract

Decades of research have examined the effects of cannabis on neurocognition. Recent advances in this field provide us with a better understanding of how cannabis use influences neurocognition both acutely (during intoxication) and non-acutely (after acute effects subside). Evidence of problems with episodic memory is one of the most consistent findings reported; however, several other neurocognitive domains appear to be adversely affected by cannabis use under various conditions. There is significant variability in findings across studies, thus a discussion of potential moderators is increasingly relevant. The purpose of this review was to 1) provide an update on research of cannabis’ acute and non-acute effects on neurocognition, with a focus on findings since 2007 and 2) suggest and discuss how neurodevelopmental issues and sex differences may influence cannabis effects on neurocognition. Finally we discuss how future investigations may lead to better understanding of the complex interplay among cannabis, stages of neurodevelopment, and sex on neurocognitive functioning.

Risk Factors for Driving After and During Marijuana Use

“…Furthermore, much like smoking tobacco cigarettes while driving (Stevens & Minton, 2001), handling marijuana materials while driving detracts from attention to the road and surroundings. Coupled with established impairments in attention and concentration during marijuana intoxication (Crane et al, 2013;Ramaekers et al, 2009), SMWD ultimately places the driver, passengers, and others at risk.…”

Δ9-Tetrahydrocannabinol decreases willingness to exert cognitive effort in male rats

“…5,6 Concerns have been raised over this rising potency of cannabis, given that higher levels of THC may induce anxiety and psychosis, and because acute cannabis use is associated with cognitive impairments in the domains of learning, memory, reasoning and attention. 7,8 Comparatively, the role of cannabinoid signalling in decision-related executive processes is unexplored. Crucial decisions in life require evaluating the costs associated with different options in light of the potential benefits obtained by those choices.…”

Marijuana Use Predicts Cognitive Performance on Tasks of Executive Function

“…Numerous studies have reported marijuana-associated impairments in frontal function, most notably during tasks that require executive control, inhibition, and decision making (for review, see Crane et al, 2013;Crean et al, 2011). Further, several investigations have specifically examined the role of age at marijuana onset, with results suggesting that earlier age at marijuana onset is related to impairment on measures of visual scanning (Ehrenreich et al, 1999), verbal IQ (Pope et al, 2003;Solowij et al, 2011), and executive function (Battisti et al, 2010;Fontes et al, 2011;Gruber et al, 2012b).…”