Cognitive reserve and brain plasticity in cannabis-using psychosis patients: A systematic review of neuroimaging and intervention studies

• Valerio Ricci ^[1] ; Giovanni Martinotti ^[2] ; Giuseppe Maina ^[1]
  1. [1] University of Turin

     University of Turin

     Torino, Italia

     
  2. [2] Department of Neurosciences, Imaging and Clinical Sciences, Università degli Studi G. D'Annunzio Chieti-Pescara, Chieti, 66100, Italy
• Localización: European journal of psychiatry, ISSN 0213-6163, Vol. 40, Nº 1, 2026
• Idioma: inglés
• DOI: 10.1016/j.ejpsy.2025.100332
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  • Abstract Background Cognitive reserve—the brain's capacity to maintain function despite neural damage—and brain plasticity—the capacity for neural reorganization—represent critical factors influencing outcomes in psychotic disorders. Their interaction with cannabis use in patients with psychotic disorders remains poorly understood.

    Objective To examine relationships between cognitive reserve, brain plasticity, and cannabis use in patients with psychotic disorders specifically investigating neuroimaging outcomes including brain structure (gray matter volume, white matter integrity) and function (neural network connectivity).

    Methods Following PRISMA guidelines, we searched four databases from 2010–2025. Studies examining patients with psychotic disorders (schizophrenia, schizoaffective disorder, first-episode psychosis) with documented cannabis use were included, encompassing the full spectrum of exposure patterns from occasional to daily use. Participants were predominantly male (69 %) with mean age 28.7 ± 8.4 years. Cognitive reserve was assessed through educational attainment, premorbid intellectual functioning (estimated IQ), or composite measures combining these indicators. Brain plasticity was measured via training-induced neuroimaging changes.

    Results Twenty-seven studies representing 3164 participants met inclusion criteria. In observational studies (n = 20), higher cognitive reserve was consistently associated with preserved gray matter volume and white matter integrity despite cannabis exposure (effect sizes d = 0.41–0.52). Intervention studies (n = 7) demonstrated that cognitive training produced measurable neuroplastic changes (d = 0.38–0.62 for structural; d = 0.45–0.59 for functional improvements). Cognitive reserve maintained network integrity specifically in cannabis-using patients. Females showed greater training-induced changes, while neuroprotection was most evident in daily cannabis users.

    Conclusions Cognitive reserve provides neuroprotection against cannabis-related brain alterations in psychotic disorders, while neuroplasticity interventions induce significant brain changes. Findings support precision medicine approaches targeting cognitive enhancement based on individual characteristics.