No differences in neural responses or performance during a cannabis cue-specific Stop-Signal Task between CUDIT-R-score-stratified cannabis users and non-users: Insights from fNIRS

Rationale: Cannabis use continues to increase globally, with a growing proportion of users meeting criteria for cannabis use disorder (CUD). Although neural differences in reward and inhibitory control systems are commonly reported in cannabis users compared to non-users, findings using behavioural tasks are inconsistent. This is possibly due to lack of differentiation between regular and more problematic users. Objectives: This study aimed to investigate whether inhibitory control performance and associated prefrontal and orbitofrontal activation differed between cannabis users stratified by CUDIT-R score and non-user controls. Methods: Participants (N = 81) were divided into three groups based on CUDIT-R scores; 30 high-CUD-risk (≥12) and 21 low-CUD-risk (<8) cannabis users, and 30 non-user controls. All completed a cannabis-cue specific Stop-Signal Task (SST) while functional near-infrared spectroscopy (fNIRS) was used to measure oxygenated (oxyHb) and deoxygenated haemoglobin (deoxyHb) concentrations in the prefrontal cortices. Behavioural performance and neural activation were compared across groups. Results: No significant behavioural or neural differences were found between the groups. Conclusions: The study found no evidence of impaired inhibitory control or differential prefrontal activation in cannabis users stratified by CUDIT-R scores. The results suggest incorporating further diagnostic stratification, multimodal imaging, and ecologically valid methods in future research to better characterise cannabis-related neural adaptations and inform clinical practice.