Attitudes to cannabis use are changing. Canada and many US States have legalised recreational use. Other countries including the UK, allow “medicinal” use. RCTs show that cannabis or its constituents (THC and CBD) are useful in chronic pain, nausea, multiple sclerosis, and in childhood epilepsy. However, the cannabis industry advocates its use in a huge range of other illnesses including opiate addiction, COVID-19, and anxiety. Unfortunately, evidence is piling up that prolonged cannabis use increases risk of psychosis; indeed, the highest incidence of psychosis across Europe is now in Amsterdam and London where high potency cannabis is most available. Thus cannabis poses a dilemma for society in how to balance the enjoyment of the many with the harm to a minority.
Professor Sir Robin Murray, Professor of Psychiatric Research, Institute of Psychiatry, Psychology & Neuroscience, King’s College London.
Chair: Dr Sotiris Posporelis