Brief report: changes in brain function during acute cannabis intoxication: preliminary findings suggest a mechanism for cannabis-induced violence.

BACKGROUND: Recent evidence suggests that cannabis use may be associated with antisocial and violent behaviour, raising the question: What brain mechanisms mediate the disinhibiting effects of cannabis on behaviour? AIMS/HYPOTHESES: To examine whether an electrocortical measure of affective impulsivity, Go/No Go contingent negative variation, is affected by acute cannabis intoxication.
METHODS: Slow brain potentials were recorded in a Go/No Go noise avoidance task from five habitual cannabis users before, during and after they smoked a cannabis reefer containing 11 mg D-9-tetrahydrocannabinol.
RESULTS: Slow brain potentials developed normally in both Go and No Go conditions before and during cannabis smoking but were severely disrupted 20-40 minutes later, coincident with peak intoxication. Cannabis effects on Go/No Go brain activity resembled those reported to occur in patients with lateral prefrontal cortex lesions. CONCLUSION/IMPLICATIONS: Our findings are preliminary, calling for larger-scale studies, to confirm the present findings and to investigate whether brain responses to cannabis intoxication differentiate those who are predisposed to suffer adverse consequences of cannabis use from those who are not.