first_imgBBC News 20 March 2019Family First Comment:people who used cannabis on a daily basis were three times more likely to have a diagnosis of first episode psychosis, compared with people who had never used cannabisThis increased to five times more likely for daily use of high potency cannabis#SayNopeToDopeSmoking potent ‘skunk-like’ cannabis increases your risk of serious mental illness, say researchers.They estimate around one in 10 new cases of psychosis may be associated with strong cannabis, based on their study of European cities and towns.In London and Amsterdam, where most of the cannabis that is sold is very strong, the risk could be much more, they say in The Lancet Psychiatry.Daily use of any cannabis also makes psychosis more likely, they found.Experts say people should be aware of the potential risks to health, even though the study is not definitive proof of harm.Lead researcher and psychiatrist Dr Marta Di Forti said: “If you decide to use high potency cannabis bear in mind there is this potential risk.”Dr Adrian James from the Royal College of Psychiatrists said: “This is a good quality study and the results need to be taken seriously.”The findingsThe researchers found:Self-reported daily cannabis use was more common among patients with first episode psychosis, compared to controls – 29.5% (or 266 out of 901) of patients versus 6.8% (84/1,237) of controlsHigh-potency cannabis use was also more common among patients with first episode psychosis, compared to controls – 37.1% (334/901) versus 19.4% (240/1,237)Across the 11 sites, people who used cannabis on a daily basis were three times more likely to have a diagnosis of first episode psychosis, compared with people who had never used cannabisThis increased to five times more likely for daily use of high potency cannabisThere was no evidence of an association between less than-weekly cannabis use and psychosis, regardless of potencyThe authors estimate that one in five new cases (20.4%) of psychosis across the 11 sites may be linked to daily cannabis use, and one in ten (12.2%) linked to use of high potency cannabis.In London, a fifth (21%) of new cases of psychosis might be linked to daily cannabis use, and nearly a third (30%) to high potency cannabis.Removing strong cannabis from the market would lower London’s psychosis incidence rate from 45.7 to 31.9 cases per 100,000 people per year, the scientists estimate.For the South London region they looked at, that would mean 60 fewer cases of psychosis each year.In London, a fifth (21%) of new cases of psychosis might be linked to daily cannabis use, and nearly a third (30%) to high potency cannabis.Removing strong cannabis from the market would lower London’s psychosis incidence rate from 45.7 to 31.9 cases per 100,000 people per year, the scientists estimate.For the South London region they looked at, that would mean 60 fewer cases of psychosis each year.READ MORE: https://www.bbc.com/news/health-47609849last_img