Adolescent-onset regular cannabis use is associated with altered neural and behavioural responses during anticipation and feedback of monetary reward and loss.

Lombardi G.; Blest-Hopley G.; Tarantini M.; O'Neill A.; Wilson R.; O'Daly O.; Giampietro V.; Bhattacharyya S. · Psychopharmacology · 2026

**Background & Methods** This neuroimaging study compared reward processing between 20 adolescent-onset regular cannabis users (≥4 days/week for 2+ years, initiated before age 18) and 20 age- and sex-matched non-users using functional MRI during the Monetary Incentive Delay Task (MIDT). The study assessed behavioral performance (reaction times, accuracy, earnings) and BOLD activation in reward-related brain regions during anticipation and outcome phases of monetary win and loss conditions. **Key Findings** • Cannabis users demonstrated altered mesocorticolimbic circuit engagement compared to non-users, including lower striatal activity during anticipation of monetary win, but higher ventral striatum and frontal pole activity during anticipation of monetary loss. • Differential ventral tegmental area (VTA) BOLD responses were observed during monetary outcomes, with cannabis users showing reduced frontal pole activity during unsuccessful loss avoidance. • Cannabis users exhibited impaired behavioral performance including lower monetary rewards earned, trend toward slower reaction times, and reduced accuracy, alongside disrupted brain-behavior coupling suggesting dissociation between neural activity and task performance. **Dosage & Administration** Cannabis use characterized as ≥4 days/week for minimum 2 years with onset before age 18. Specific cannabinoid concentrations, THC:CBD ratios, consumption routes, and daily quantities not reported. **Safety & Adverse Effects** Not reported. Study focused on neurobiological correlates rather than adverse effect documentation. **Evidence Quality** This is a preliminary neuroimaging study with significant limitations. The small sample size (N=40) limits generalizability. The cross-sectional design precludes causal inference; observed differences may reflect pre-existing susceptibility rather than cannabis-induced changes. Potential confounders including concurrent substance use, psychiatric comorbidities, and socioeconomic factors are not comprehensively addressed. The study provides correlational evidence of altered reward processing but cannot establish mechanistic causation. Findings are preliminary and require replication in larger longitudinal cohorts to establish developmental trajectories and clinical significance. The disrupted brain-behavior coupling is noteworthy but requires further investigation to understand functional implications.

More recent cannabis research