Neuropsychological Performance in Long-term Cannabis Users: Investigation of the question of residual deficits in cognitive functioning after longterm heavy cannabis use has been inconclusive. A new study by Harrison Pope and associates from McLean Hospital compared active heavy users, abstinent but formerly heavy users, and non-cannabis-using controls on a comprehensive neuropsychological battery including measures of general intellectual function, abstraction

ability, sustained attention, verbal fluency, and ability to learn

and recall new verbal and visuospatial information. Findings: “Some cognitive deficits appear detectable at

least 7 days after heavy cannabis use but appear reversible

and related to recent cannabis exposure rather than irreversible

and related to cumulative lifetime use.” Archives of General Psychiatry