“Cannabis, widely used for both medical and non-medical purposes, primarily contains Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD).
This review aims to clarify how the molecular and receptor-level mechanisms of CBD, compared with Δ9-THC, shape its distinct therapeutic profile and low liability for addiction, thereby informing the safer clinical application of CBD-containing interventions to schizophrenia.
CBD exerts sedative and therapeutic effects, including in treatment-resistant epilepsy, and acts in part via CB1 and CB2 receptors that also mediate Δ9-THC actions. While Δ9-THC activates these receptors as an agonist, triggering Gi-coupled signaling cascades such as MAPK pathways and suppressing presynaptic monoamine release, CBD functions as a non-competitive negative allosteric CB1 modulator and non-competitive antagonist of Δ9-THC. These distinct intracellular signaling mechanisms are considered to underlie the markedly different pharmacological profiles and abuse liabilities of Δ9-THC and CBD.
CBD also engages multiple CNS targets beyond CB1 and CB2, including GPR55, TRPV1 and ENT1, which are implicated in anticonvulsant, anti-inflammatory, analgesic and neuroprotective actions. Although GPR55 pharmacology remains controversial and Δ9-THC shows inconsistent activity at this receptor, converging evidence indicates that CBD can antagonize CB1/CB2 and modulate atypical cannabinoid-sensitive proteins. Excessive activation of certain serotonin receptors, including 5-HT1A/2A, are thought to underlie some symptoms of psychosis.
These diverse molecular actions are thought to underlie CBD’s broad therapeutic potential across seizures and other CNS disorders, providing a mechanistic rationale for exploring CBD as a treatment option for psychosis in schizophrenia and stimulant-induced psychotic states.”
https://pubmed.ncbi.nlm.nih.gov/42658346/
https://link.springer.com/article/10.1007/s11064-026-04860-1