title: Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment.
abstract: Community-based studies suggest that cannabis products that are high in Δ⁹-tetrahydrocannabinol (THC) but low in cannabidiol (CBD) are particularly hazardous for mental health. Laboratory-based studies are ideal for clarifying this issue because THC and CBD can be administered in pure form, under controlled conditions. In a between-subjects design, we tested the hypothesis that pre-treatment with CBD inhibited THC-elicited psychosis and cognitive impairment. Healthy participants were randomised to receive oral CBD 600 mg (n=22) or placebo (n=26), 210 min ahead of intravenous (IV) THC (1.5 mg). Post-THC, there were lower PANSS positive scores in the CBD group, but this did not reach statistical significance. However, clinically significant positive psychotic symptoms (defined a priori as increases ≥ 3 points) were less likely in the CBD group compared with the placebo group, odds ratio (OR)=0.22 (χ²=4.74, p<0.05). In agreement, post-THC paranoia, as rated with the State Social Paranoia Scale (SSPS), was less in the CBD group compared with the placebo group (t=2.28, p<0.05). Episodic memory, indexed by scores on the Hopkins Verbal Learning Task-revised (HVLT-R), was poorer, relative to baseline, in the placebo pre-treated group (-10.6 ± 18.9%) compared with the CBD group (-0.4% ± 9.7 %) (t=2.39, p<0.05). These findings support the idea that high-THC/low-CBD cannabis products are associated with increased risks for mental health.
authors.affiliation: The Biomedical Research Centre, Institute of Psychiatry, King's College London, UK.
authors.forename: Amir
authors.initials: A
authors.lastname: Englund
authors.forename: Paul D
authors.initials: PD
authors.lastname: Morrison
authors.forename: Judith
authors.initials: J
authors.lastname: Nottage
authors.forename: Dominic
authors.initials: D
authors.lastname: Hague
authors.forename: Fergus
authors.initials: F
authors.lastname: Kane
authors.forename: Stefania
authors.initials: S
authors.lastname: Bonaccorso
authors.forename: James M
authors.initials: JM
authors.lastname: Stone
authors.forename: Avi
authors.initials: A
authors.lastname: Reichenberg
authors.forename: Rudolf
authors.initials: R
authors.lastname: Brenneisen
authors.forename: David
authors.initials: D
authors.lastname: Holt
authors.forename: Amanda
authors.initials: A
authors.lastname: Feilding
authors.forename: Lucy
authors.initials: L
authors.lastname: Walker
authors.forename: Robin M
authors.initials: RM
authors.lastname: Murray
authors.forename: Shitij
authors.initials: S
authors.lastname: Kapur
mesh_terms: D000328:Adult; D002185:Cannabidiol / Q000009:adverse effects / Q000494:pharmacology*; D002188:Cannabis / Q000009:adverse effects*; D060825:Cognitive Dysfunction / Q000139:chemically induced* / Q000517:prevention & control; D004311:Double-Blind Method; D013759:Dronabinol / Q000009:adverse effects* / Q000037:antagonists & inhibitors*; D004347:Drug Interactions; D005260:Female; D006624:Hippocampus / Q000187:drug effects; D006801:Humans; D007858:Learning / Q000187:drug effects; D008297:Male; D008569:Memory Disorders / Q000139:chemically induced* / Q000517:prevention & control; D010259:Paranoid Disorders / Q000139:chemically induced* / Q000517:prevention & control
chemical_list: D002185:Cannabidiol; D013759:Dronabinol