Doctors have long known that cannabis use can trigger psychosis. However, new research suggests that the effect of cannabis use on young teens is stronger than ever imagined. Teens who use cannabis are 11 times more likely to have a psychotic episode than those who don't, according to new research. "We found a very strong association between cannabis use and risk of psychotic disorder in adolescence. Surprisingly, we didn't find evidence of association in young adulthood," explained lead study author André McDonald from the University of Toronto. Psychotic episodes involve entering a dangerous psychiatric state and losing connection with reality. The study found that 5 out of every 6 teens admitted to the hospital for a psychotic episode had a history of marijuana use. McDonald also noted that "most teens who are diagnosed with a psychotic disorder likely have a history of cannabis use."