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Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study
Published on: August 18, 2020
Neuropsychological performance in long-term cannabis users
H G Pope1, A J Gruber, J I Hudson
1McLean Hospital, Harvard Medical School, 115 Mill St, Belmont, MA 02478, USA.
Archives of General Psychiatry
|November 1, 2001
Summary
Heavy cannabis use can cause short-term cognitive deficits, particularly in memory recall. These effects appear reversible within 28 days and are linked to recent use, not cumulative lifetime exposure.
Area of Science:
- Neuroscience
- Psychology
- Pharmacology
Background:
- Cannabis is the most frequently used illicit drug in the U.S.
- Long-term cognitive impacts of cannabis use are not well understood.
Purpose of the Study:
- To investigate the cognitive effects of heavy cannabis use.
- To determine if cognitive deficits are related to recent or cumulative use.
Main Methods:
- Recruited three groups: current heavy users, former heavy users, and controls.
- Administered a 28-day washout period with monitored urine samples.
- Assessed cognitive functions including memory, attention, and verbal fluency via neuropsychological testing.
Main Results:
- Current heavy cannabis users showed significant recall deficits at 0, 1, and 7 days post-washout.
- Deficits correlated with urinary THC metabolite levels at study entry.
- No significant cognitive differences were observed between groups by day 28.
Conclusions:
- Cognitive deficits following heavy cannabis use are detectable up to 7 days.
- These deficits appear reversible and linked to recent exposure.
- Findings suggest cannabis's cognitive impact is not cumulative or irreversible.
