Chronic cannabis users show altered neurophysiological functioning on Stroop task conflict resolution

Abstract

These findings indicate that chronic use of cannabis may impair the brain's ability to respond optimally in the presence of events that require conflict resolution and hold implications for the ability to refrain from substance misuse and/or maintain substance abstention behaviours.

Marijuana Use Predicts Cognitive Performance on Tasks of Executive Function

“…Chronic, heavy marijuana smokers have previously demonstrated impaired performance on both the Stroop and WCST relative to control participants (Battisti et al, 2010;Fontes et al, 2011;Gruber et al, 2012b;Lane et al, 2007), and prior work has noted that early-onset marijuana smokers accounted for the between-group differences across multiple cognitive domains (Ehrenreich et al, 1999;Fontes et al, 2011;Gruber et al, 2012b;Pope et al, 2003). Those findings, combined with results from the current study, highlight the importance of examining age at onset of marijuana use.…”

“…Our results complement previous research using both correlation and regression analyses to address the role of marijuana use variables. Earlier age at marijuana onset has previously been shown to correlate with impaired performance on the Stroop and WCST tasks (Battisti et al, 2010;Gruber et al, 2012b), whereas increased frequency and magnitude of marijuana use have been shown to be related to impairment in psychomotor speed, sustained attention, and cognitive inhibition (Lisdahl & Price, 2012), as well as verbal memory (Solowij et al, 2011) and executive function (Gruber et al, 2012b;Harvey et al, 2007). In addition, this study incorporated logistic regression techniques and demonstrated that increased total perseverative errors on the WCST is a moderately accurate predictor of marijuana smokers, suggesting that this may be a clinical characteristic of chronic, heavy marijuana use.…”

“…In addition, the current study's inclusion criteria required all subjects to refrain from using marijuana for 12 hours before completing study procedures; a similar time frame of abstinence has been used in other studies (Battisti et al, 2010;Gruber & Yurgelun Todd, 2005;Gruber et al, 2011Gruber et al, , 2012aGruber et al, , 2012bGruber et al, , 2014Harvey et al, 2007;Solowij et al, 2011). This approach was designed to prevent impairment resulting from acute intoxication.…”

“…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). Gruber and colleagues (2012b) found that mari-juana smokers performed more poorly than healthy control subjects on tasks of executive function, including the Wisconsin Card Sorting Test (WCST) and Stroop Color Word Test (Stroop).…”

Cannabis Abstinence During Treatment and One-Year Follow-Up: Relationship to Neural Activity in Men

“…For example, chronic cannabis users perform less well than healthy peers on measures of memory, information processing, and cognitive control (eg, Schreiner and Dunn, 2012;Solowij et al, 2002, but also see Takagi et al, 2011). Further, compared with non-drug-using adults, cannabis users often exhibit lower neural activity during performance on memory, learning, and cognitive-control tasks (including the Stroop color-word interference task) across several brain regions, including prefrontal cortex (Battisti et al, 2010;Eldreth et al, 2004;Gruber and Yurgelun-Todd, 2005, but c.f., Harding et al, 2012).…”