Project ID NS-MH2023_37


Co Supervisor 1A IoPPN/AddictionsWebsite

Co Supervisor 1B IoPPN/AddictionsWebsite

Exploring the acute interactions of THC and CBD in heavy cannabis users

Laws regulating cannabis are rapidly changing globally, with Uruguay, Canada, and several US states now permitting recreational use. Concurrently, cannabis potency (of ∆9-tetrahydrocannabinol, THC) has increased in most parts of the world, and research suggests high-potency cannabis has a stronger association with risks of psychosis, cognitive impairment and cannabis addiction. However, recent evidence shows the second most prevalent compound in the cannabis plant, cannabidiol (CBD), has anti-psychotic and cognitively protective effects, and may help prevent or treat cannabis addiction.

This project explores the effects of CBD on THC-elicited negative effects in people with heavy problematic cannabis use.

The project will utilise multiple study designs:
An online survey of regular cannabis users, who will complete a series of cognitive assessments while using their own cannabis at home (Year 1).
A highly novel remote experimental study, where pharmacy-prepared cannabis with different doses of THC are delivered to participants along with a randomly-assigned blinded oral dose of CBD or placebo. Participants will self-administer study drugs and will complete cognitive tasks and clinical assessments via an online platform and videoconference (Year 2).
An experimental psychopharmacology study in heavy users in a controlled setting who will, over separate visits, be administered different doses of THC with or without a CBD pre-treatment (Year 2-3).

The successful candidate will join a world-leading experimental psychopharmacology unit. They will gain skills administering cognitive and psychological symptom assessments, experience designing and conducting experimental research with scheduled drugs, and will contribute to a rapidly emerging field of high policy relevance internationally.

Representative Publications

Marsden J, et al. Medicines associated with dependence or withdrawal: a mixed-methods public health review and national database study in England. Lancet Psychiatry. 2019. PMID: 31588045

Metrebian N, Weaver T, Goldsmith K on behalf of the Contingency Management Programme Team, et al. Using a pragmatically adapted, low-cost contingency management intervention to promote heroin abstinence in individuals undergoing treatment for heroin use disorder in UK drug services (PRAISE): a cluster randomised trial. BMJ Open 2021;11: e046371.