An EEG and Behavioral Analysis of Response Inhibition in Cannabis Users: The Impact of Trait Impulsivity

Abstract

This study investigated the relationship between cannabis use severity, trait impulsivity, and response inhibition using both behavioral and electrophysiological measures. Eighteen cannabis users completed a stop-signal task (SST) while EEG data were recorded. Cannabis use severity, assessed via the Cannabis Use Disorders Identification Test (CUDIT), initially predicted mean stop-signal reaction time (SSRT), an index of behavioral inhibition. Trait impulsivity, measured using the Barratt Impulsiveness Scale (BIS-11), also significantly predicted SSRT. Mediation analysis revealed a full mediation effect, whereby cannabis use severity predicted SSRT only through trait impulsivity, suggesting impulsivity may be a key mechanism linking cannabis use to inhibitory control deficits. EEG data from 15 participants (3 excluded due to artifacts) showed that cannabis use severity did not significantly predict P3 amplitudes during successful inhibition trials. However, in failed inhibition trials, higher cannabis use severity was associated with lower P3 amplitudes, potentially reflecting diminished later-stage error processing. These findings underscore the role of trait impulsivity in cannabis-related inhibitory impairments and suggest cannabis use may disrupt neural mechanisms involved in error monitoring. The small sample size and the limited sensitivity of the CUDIT for capturing dose-dependent effects are noted as key limitations of the study. Further research with larger samples and more nuanced measures of cannabis exposure is needed to better understand these relationships.