BJPsych Open
August 25, 2026
Edward Chesney, Millie Lloyd, Sébastien Brodeur et al.
BACKGROUND: Cannabis use is common in people with psychosis and is associated with poor outcomes. AIMS: To assess insight into cannabis use disorder, perceptions about how cannabis use influences mental health and the desire to change cannabis use among people with psychotic disorders. METHOD: Adults with a psychotic disorder and comorbid cannabis use disorder were asked about the impact of...
Drug and Alcohol Dependence
July 1, 2026
Daniel L. Hall, Edward Chesney, Claire Mokrysz et al.
The presence of cannabidiol (CBD) in cannabis may alter cannabinoid pharmacokinetics, however previous research has produced mixed results. Furthermore, no prior research has explored how cannabinoid pharmacokinetics are moderated by age. Using vaporised and inhaled cannabis, we aimed to (1) examine the effect of CBD on the plasma concentration of delta-9-tetrahydrocannabinol (THC) and its...
Neuroscience & Biobehavioral Reviews
June 3, 2026
Isabella Goodwin, Dominic Oliver, Edward Chesney et al.
Global shifts towards the liberalisation of cannabis policies have increased the potency of cannabis products, alongside their accessibility, diversity, and the number of inexperienced cannabis consumers. There is a lack of systematic evidence on the subjective effects of cannabis' main psychoactive compound, Δ9-tetrahydrocannabinol (THC). We systematically reviewed and meta-analysed data from...
Neuropsychopharmacology
November 2025
Edward Chesney, Dominic Oliver, Ananya Sarma et al.
In patients with schizophrenia, cannabis use exacerbates symptoms and can lead to a relapse of psychosis. Some experimental studies in healthy volunteers suggest that pre-treatment with cannabidiol (CBD) may reduce these effects, but others do not. Here, we investigated whether pre-treatment with CBD ameliorates the acute adverse effects of cannabis in patients with schizophrenia. Participants...
The British Journal of Psychiatry
December 3, 2024
Edward Chesney, Thomas J. Reilly, Fraser Scott et al.
Background Abrupt cessation of heavy cannabis use can cause a withdrawal syndrome characterised by irritability, anxiety, insomnia, reduced appetite and restlessness. Recent reports have also described people in whom cannabis withdrawal immediately preceded the acute onset of psychosis. Aims To identify cases of psychosis associated with cannabis withdrawal. Method We completed a systematic...
Addiction
February 2024
Dominic Oliver, Amir Englund, Edward Chesney et al.
To test how attentional bias and explicit liking are influenced by delta-9-tetrahydrocannabinol (THC) and whether these effects are moderated by cannabidiol (CBD). Double-blind, randomised, within-subjects cross-over study. NIHR Wellcome Trust Clinical Research Facility at King's College Hospital, London, United Kingdom. Forty-six infrequent cannabis users (cannabis use <1 per week). Across...
Cannabis and Cannabinoid Research
February 1, 2024
Edward Chesney, Will Lawn, Philip Mcguire
Introduction: Cannabis use is common in people with psychotic disorders and is associated with the exacerbation of symptoms, poor treatment adherence, and an increased risk of relapse. Accurate assessment of cannabis use is thus critical to the clinical management of psychosis. Discussion: Cannabis use is usually assessed with self-report questionnaires that were originally developed for...
Frontiers in Psychiatry
2024
Xinyi Liang, Maria-Mihaela Avram, Toni Gibbs-Dean et al.
Cannabis users present an important group for investigating putative mechanisms underlying psychosis, as cannabis-use is associated with an increased risk of psychosis. Recent work suggests that alterations in belief-updating under uncertainty underlie psychosis. We therefore compared belief updating under uncertainty between cannabis and non-cannabis users. 49 regular cannabis users and 52...
Psychiatry and Clinical Neurosciences
April 18, 2023
Lucy Chester, Lucia Valmaggia, Matthew J. Kempton et al.
Evidence for case–control studies suggests that cannabis use is a risk factor for the development of psychosis. However, there have been limited prospective studies and the direction of this association remains controversial. The primary aim of the present study was to examine the association between cannabis use and the incidence of psychotic disorders in people at clinical high risk of...
Addiction
February 8, 2023
Will Lawn, Katie Trinci, Claire Mokrysz et al.
36 citations
Abstract Background and Aims Long‐term harms of cannabis may be exacerbated in adolescence, but little is known about the acute effects of cannabis in adolescents. We aimed to (i) compare the acute effects of cannabis in adolescent and adult cannabis users and (ii) determine if cannabidiol (CBD) acutely modulates the effects of delta‐9‐tetrahydocannabinol (THC). Design Randomised, double‐blind,...
Cannabis and Cannabinoid Research
December 9, 2022
Lucy Chester, Amir Englund, Edward Chesney et al.
20 citations
Background: The effects of cannabis are thought to be mediated by interactions between its constituents and the endocannabinoid system. Delta-9-tetrahydrocannabinol (THC) binds to central cannabinoid receptors, while cannabidiol (CBD) may influence endocannabinoid function without directly acting on cannabinoid receptors. We examined the effects of THC coadministered with different doses of CBD...
Neuropsychopharmacology
November 16, 2022
Amir Englund, D. Oliver, Edward Chesney et al.
As countries adopt more permissive cannabis policies, it is increasingly important to identify strategies that can reduce the harmful effects of cannabis use. This study aimed to determine if increasing the CBD content of cannabis can reduce its harmful effects. Forty-six healthy, infrequent cannabis users participated in a double-blind, within-subject, randomised trial of cannabis preparations...