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Updated: May 22, 2026
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Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study
Published on: August 18, 2020
Functional connectivity in brain networks underlying cognitive control in chronic cannabis users
Ian H Harding1, Nadia Solowij, Ben J Harrison
1Department of Psychiatry, Melbourne Neuropsychiatry Centre, University of Melbourne and Melbourne Health, Melbourne, VIC, Australia. hardingi@unimelb.edu.au
Summary
Long-term cannabis use alters brain connectivity, enhancing attention control. These brain changes may compensate for potential cognitive deficits in regular cannabis users.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Addiction Research
Background:
- Cognitive control is crucial for daily functioning and is implicated in addiction.
- The long-term effects of regular cannabis use on cognitive control remain unclear.
- Understanding these effects is vital for addressing maladaptive drug-taking behaviors.
Purpose of the Study:
- To investigate the long-term effects of daily cannabis use on brain function related to cognitive control.
- To examine functional interactions between brain regions during cognitive control tasks in cannabis users versus controls.
Main Methods:
- Utilized the Multi-Source Interference Task (MSIT) with functional magnetic resonance imaging (fMRI).
- Employed psychophysiological interaction (PPI) methods to analyze brain connectivity.
- Compared long-term daily cannabis users (n=21) with matched non-using controls (n=21).
Main Results:
- No significant differences in behavioral performance or task-related brain activation were found between groups.
- Cannabis users exhibited increased functional connectivity between the prefrontal cortex and occipitoparietal cortex under cognitive demand.
- This enhanced connectivity correlated positively with age of onset and lifetime cannabis exposure.
Conclusions:
- Long-term cannabis use may lead to compensatory changes in brain networks supporting cognitive control.
- Increased prefrontal-occipitoparietal connectivity suggests altered attentional control mechanisms in users.
- These neural adaptations might mitigate potential cognitive impairments associated with chronic cannabis consumption.
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