Effects of acute smoked marijuana on complex cognitive performance.
Carl L. Hart, W Van Gorp, M Haney, Richard W Foltin, M W Fischman
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology November 2001 DOI: 10.1016/s0893-133x(01)00273-1 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Within-participant double-blind experimental study Peer reviewed |
|---|---|
| Sample size | 18 |
| Population | Healthy experienced marijuana smokers (8 females, 10 males) averaging 24 marijuana cigarettes per week |
| Dose | 0%, 1.8%, or 3.9% Delta(9)-THC w/w |
| Duration | Three sessions separated by at least 72 hours |
| Measures | computerized cognitive tasks (not specified by name), blood pressure, heart rate, subjective effects ratings |
| Topics | Cannabis |
| Key findings | Acute marijuana smoking increased premature responses and task completion times but had no effect on accuracy in measures of cognitive flexibility, mental calculation, and reasoning. Heart rate and subjective effects increased in a Delta(9)-THC concentration-dependent manner, indicating minimal effects on complex cognitive performance in experienced users. |
Abstract
Although the ability to perform complex cognitive operations is assumed to be impaired following acute marijuana smoking, complex cognitive performance after acute marijuana use has not been adequately assessed under experimental conditions. In the present study, we used a within-participant double-blind design to evaluate the effects acute marijuana smoking on complex cognitive performance in experienced marijuana smokers. Eighteen healthy research volunteers (8 females, 10 males), averaging 24 marijuana cigarettes per week, completed this three-session outpatient study; sessions were separated by at least 72-hrs. During sessions, participants completed baseline computerized cognitive tasks, smoked a single marijuana cigarette (0%, 1.8%, or 3.9% Delta(9)-THC w/w), and completed additional cognitive tasks. Blood pressure, heart rate, and subjective effects were also assessed throughout sessions. Marijuana cigarettes were administered in a double-blind fashion and the sequence of Delta(9)-THC concentration order was balanced across participants. Although marijuana significantly increased the number of premature responses and the time participants required to complete several tasks, it had no effect on accuracy on measures of cognitive flexibility, mental calculation, and reasoning. Additionally, heart rate and several subjective-effect ratings (e.g., "Good Drug Effect," "High," "Mellow") were significantly increased in a Delta(9)-THC concentration-dependent manner. These data demonstrate that acute marijuana smoking produced minimal effects on complex cognitive task performance in experienced marijuana users.