High potency cannabis is associated with tripled risk of psychosis, study indicates

Users of high potency (“skunk-like”) cannabis are three times as likely to have a psychotic episode as people who never use cannabis, and the risk is fivefold in people who smoke this form of the drug every day, a study published in Lancet Psychiatry this week concludes.1

Between 1 May 2005 and 31 May 2011 researchers from the Institute of Psychiatry, Psychology and Neuroscience at King’s College London studied 410 patients who had experienced a first episode of psychosis and collected data on their cannabis use. These data were compared with data collected from 370 people from the …