Neural correlates of performance monitoring in chronic cannabis users and cannabis-naive controls.

Chronic cannabis use is associated with residual negative effects on measures of executive functioning. However, little previous work has focused specifically on executive processes involved in performance monitoring in frequent cannabis users. The present study investigated event-related potential (ERP) correlates of performance monitoring in chronic cannabis users. The error-related negativity (ERN) and error positivity (Pe), ERPs sensitive to performance monitoring, were recorded from 30 frequent cannabis users (mean usage=5.52 days/week) and 32 cannabis-naïve control participants during a speeded stimulus discrimination task. The "oddball" P3 ERP was recorded as well. Users and controls did not differ on the amplitude or latency of the ERN; however, Pe amplitude was larger among users. Users also showed increased amplitude and reduced latency of the P3 in response to infrequent stimuli presented during the task. Among users, urinary cannabinoid metabolite levels at testing were unrelated to ERP outcomes. However, total years of cannabis use correlated negatively with P3 latency and positively with P3 amplitude, and age of first cannabis use correlated negatively with P3 amplitude. The results of this study suggest that chronic cannabis use is associated with alterations in neural activity related to the processing of motivationally-relevant stimuli (P3) and errors (Pe).