Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment
Amir Englund, Paul D. Morrison, Judith Nottage, Dominic Hague, Fergus Kane, Stefania Bonaccorso, James Stone, Avi Reichenberg, Rudolf Brenneisen, David Holt, Amanda Feilding, Lucy Walker, Robin Murray, Shitij Kapur
Journal of Psychopharmacology October 5, 2012 DOI: 10.1177/0269881112460109 via OpenAlex
Summary
AI-generated from the abstractPre-treatment with 600 mg of cannabidiol (CBD) reduced the likelihood of clinically significant psychotic symptoms and paranoia caused by intravenous delta-9-tetrahydrocannabinol (THC, 1.5 mg) in healthy volunteers. Participants who received CBD before THC had lower scores on the State Social Paranoia Scale and smaller declines in episodic memory compared with those who received placebo before THC. The odds of experiencing a clinically significant increase in positive psychotic symptoms were about 78% lower in the CBD group. These results support the view that cannabis products high in THC and low in CBD pose greater mental health risks.
Study at a glance
| Characteristics | Randomized controlled trial Peer reviewed |
|---|---|
| Sample size | 48 |
| Population | Healthy participants |
| Intervention | Cannabidiol (CBD) |
| Dose | 600 mg oral CBD, 1.5 mg intravenous THC |
| Topics | Cannabis CBD |
| Keywords | Paranoia Placebo Psychology |
| Citations | 463 |
| Key finding | Pre-treatment with 600 mg CBD reduced THC-elicited paranoia and the odds of clinically significant positive psychotic symptoms, and mitigated THC-induced 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.