Frontiers in Psychology
May 14, 2020
Marco Colizzi, Mirella Ruggeri, Sagnik Bhattacharyya
50 citations
Evidence suggests a dose-response relationship between cannabis use and psychosis risk, driven by frequent use and high-potency cannabis with high delta-9-tetrahydrocannabinol (Δ9-THC) concentration. Δ9-THC induces transient psychosis-like symptoms in healthy individuals, while low-potency varieties may be less harmful due to lower Δ9-THC and the presence of cannabidiol (CBD), which may mitigate Δ9-THC's detrimental effects. CBD may have protective and therapeutic properties for psychosis. Similar patterns emerge for cognition: Δ9-THC impairs cognition, while CBD prevents such effects and enhances cognition alone. Molecular evidence shows Δ9-THC acts as a partial agonist and CBD as an inverse agonist/antagonist at cannabinoid receptors, with opposite effects on brain function, explaining intoxicating and therapeutic effects.
Journal of psychopharmacology (Oxford, England)
April 24, 2026
Marco Colizzi, Elisa Morandin, Veronica Croccia et al.
In adults with treatment-resistant depression, higher baseline levels of the inflammatory marker interleukin-6 (IL-6) were associated with more rapid symptom reduction after intranasal esketamine treatment, while lower IL-6 predicted greater symptom severity and higher disability. IL-6 levels themselves did not change over the 24-week open-label phase 2 trial. The finding suggests that inflammation may play a role in treatment resistance and that baseline IL-6 could help guide personalized treatment decisions.
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology
July 17, 2026
Mauro Scala, Enrico Magrini, Ivana Leccisotti et al.
Suicide remains a leading cause of early death worldwide, and current treatments are limited by slow onset, short durability, or poor tolerability. This narrative review of 34 studies over the past decade examined pharmacological and neuromodulation interventions for suicidal ideation or suicide attempt that are not yet approved for these uses. Across controlled trials, suicidal ideation commonly improved within days to weeks. Some trials reported reductions in suicidal ideation beyond changes in depression scores, suggesting partial independence, though evidence remains inconsistent. Encouraging results were reported for NMDA-related drugs, opioid-system modulation, ayahuasca, and certain neuromodulation techniques, while non-medical cannabis use was associated with worse suicidal ideation trajectories.
Healthcare
August 16, 2022
Riccardo Bortoletto, Marco Colizzi
Autism spectrum individuals are especially vulnerable to the pro-psychotic effects of cannabinoid exposure, which increases their risk of psychosis and may be passed to their children. Cannabis exposure in these individuals appears to cause disruptive epigenetic changes that can be inherited across generations in brain areas critical for schizophrenia. These cannabinoid-induced epigenetic effects also make autism candidate genes more vulnerable to later disruption, potentially leading to psychosis. The findings support a developmental link between autism and psychosis through endocannabinoid system modulation, though this evidence has been underappreciated.