People with cannabis use disorder showed reduced prefrontal cortex activity when evaluating effort and reward opportunities, but increased posterior brain activity when integrating effort-reward information, suggesting altered motivation processing.
Addiction neuroscientists, psychiatrists treating CUD, motivation researchers
People with CUD showed decreased prefrontal but increased posterior cortical activity during effort-reward processing
What the researchers found
The CUD group showed decreased ventromedial prefrontal cortex activity when initially evaluating effort and reward cues (Cue1), and increased activity in parietal, temporal, and cingulate regions during effort-reward integration (Cue2). Despite these neural differences, both groups made similar behavioral choices. In the CUD group specifically, ventral striatum activity during effort cues was associated with willingness to accept high-effort/high-reward trials.
Why it matters
Low motivation is a hallmark clinical feature of cannabis use disorder, but its brain basis has been poorly understood. This study reveals specific neural circuitry differences in how people with CUD process effort-reward tradeoffs, pointing toward potential treatment targets.
The numbers in context
21 CUD participants, 20 healthy controls; decreased vmPFC activity during prospective encoding in CUD; increased parietal, temporal, fusiform, cingulate, claustrum activity during integration in CUD; behavioral choices similar between groups; ventral striatum activity correlated with high-effort acceptance in CUD group
How the study worked
fMRI study comparing 21 individuals with cannabis use disorder and 20 healthy controls during a sequential effort-based decision-making task. The task separated the evaluation of effort/reward cues from their integration and subsequent choice behavior.
What this study cannot tell us
Small sample (21 CUD, 20 controls), cross-sectional design cannot determine if neural differences preceded or resulted from cannabis use, task used monetary rewards which may not capture real-world motivation, no assessment of acute cannabis effects, no dose-response analysis
How to read the evidence
Small neuroimaging study with novel task design; provides mechanistic insights but limited sample size and cross-sectional design
When this study was published
Published 2025
The bigger picture
The "amotivational syndrome" associated with cannabis use has been debated for decades. This study provides some of the first neuroimaging evidence that motivation processing is specifically altered in CUD, not globally impaired but reorganized across different brain circuits.
Questions still open
- Would the neural differences normalize with sustained abstinence? Do these patterns predict real-world motivational deficits better than self-report measures? Could these circuits be targeted with neurostimulation or behavioral interventions?
Common questions
Does cannabis use disorder affect motivation in the brain?
Do people with CUD make worse decisions about effort?
Read the original research
A behavioural and neurobiological assessment of effort-based decision-making in cannabis use disorder: An initial/preliminary investigation.
Cognitive, affective & behavioral neuroscience, 25(5), 1496-1514
Citation
Brassard, Sarah L; Dosanjh, Jadyn; Cooper, Jessica; Weber, Jochen; Zald, David; MacKillop, James; Balodis, Iris M. (2025). A behavioural and neurobiological assessment of effort-based decision-making in cannabis use disorder: An initial/preliminary investigation.. Cognitive, affective & behavioral neuroscience, 25(5), 1496-1514. https://doi.org/10.3758/s13415-025-01308-x
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