Investigators at New York State’s Psychiatric Institute and Columbia University assessed the impact of acute cannabis intoxication on the decision-making abilities of 36 subjects, as assessed by the Iowa Gambling Task performance test. Volunteers completed the Gambling Task once sober and three times after smoking cannabis or placebo.

Though cannabis intoxication increased the time required for subjects to complete their tasks, volunteers’ accuracy was not adversely impacted by pot.

"[A]dvantageous card selection and money earned on the task were not disrupted by marijuana," authors concluded. "These data are consistent with previous findings that indicated that speed of performance on tests of executive function, but not accuracy, is disrupted in experienced marijuana users during marijuana intoxication."