Cannabis and Cannabinoid Research
December 9, 2022
Lucy Chester, Amir Englund, Edward Chesney et al.
20 citations
Inhaling vaporized cannabis containing 10 mg of THC acutely increased blood levels of the endocannabinoid anandamide by 18% and several related noncannabinoid lipids, but adding 10, 20, or 30 mg of CBD did not alter these effects. Over four sessions spaced about two weeks apart, pre-inhalation levels of anandamide and one related compound progressively declined, possibly due to repeated THC exposure or reduced anxiety. The findings suggest that CBD, at the doses tested, does not modulate THC's acute influence on endocannabinoid concentrations, though higher or chronic CBD doses might have an effect.
British Journal of Psychiatry
December 3, 2024
E. Chesney, Thomas J. Reilly, Fraser Scott et al.
Abruptly stopping heavy, daily cannabis use can trigger psychosis, both in people experiencing their first episode and in those with a pre-existing psychotic disorder. A systematic review of 21 studies identified 44 individuals whose psychosis began after cannabis withdrawal, and a health-record search found another 68 cases. Almost all were daily users who stopped abruptly. Those who resumed cannabis after the acute psychotic episode were far more likely to relapse than those who abstained (odds ratio 13.9). The findings indicate that acute psychotic symptoms can emerge after cannabis cessation, not only during its use.
Frontiers in psychiatry
January 1, 2024
Xinyi Liang, Maria-Mihaela Avram, Toni Gibbs-Dean et al.
Regular cannabis users show no overall difference from non-users in how they update their beliefs under uncertainty, a cognitive process linked to psychosis. Both groups correctly adjusted their confidence and learning when uncertainty changed. However, among cannabis users, those who used cannabis more frequently performed worse on the task than less frequent users. This pattern resembles the abnormal belief-updating seen in psychosis, suggesting that frequent cannabis use may share a cognitive risk marker with psychosis, even though cannabis use status alone does not impair this process.