Cannabidiol (CBD), a once-considered inert cannabis constituent, is one of two primary
constituents of cannabis, alongside delta-9-tetrahydrocannabinol (∆9-THC/THC). In the
last 30 years, CBD has become implicated with a range of pharmaceutical mechanisms
of great therapeutic interest and utility. This review details the literature speculating
CBD’s attenuation of psychotic symptoms, particularly in light of a marked elevation in
mean THC concentrations, and a concomitant decline in CBD concentrations in the
prevalent U.K street market cannabis derivatives since c. 2000. CBD is purported to
exhibit pharmacology akin to established atypical antipsychotics, whilst THC has been
implicated with the precipitation of psychosis, and the induction of associated symptoms. The aim of the review was to clarify the conjecture surrounding CBD’s antipsychotic
efficacy, before going on to detail prominent theories about its associated
pharmacodynamics. Were CBD’s antipsychotic efficacy established, then there is
potential for major latent anthropological repercussions to manifest, such as significant
elevations in psychosis manifestations in the U.K. The review found a largely affirmative
body of evidence asserting CBD’s antipsychotic efficacy. CBD exhibited capacity to
attenuate natural and artificially induced psychoses in both animal and human cohorts the latter of which included individuals considered resistant to conventional treatment.
CBD also shows promising potential for use as an antipsychotic drug for Parkinson’s
disease (PD) patients with psychosis, owing to its low rate of extra-pyramidal side-effect
induction. A range of potential pharmacological mechanisms behind CBD’s neuroleptic
pharmacology are outlined, with particular emphasis on its prevention of the hydrolysis
and reuptake of the endogenous cannabinoid, anandamide. However, given the nebular
aetiological basis for psychoses, explicit conclusions on how CBD attenuates psychotic
symptoms remains to be determined.
