Cannabis Use Disorder Altered How the Brain Weighs Effort Against Reward on fMRI

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.

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.

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 "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.

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