People with a certain gene combination that exists in 25 percent of the population had that heightened risk, Otago University’s Professor Richie Poulton told the Cannabis and Health Symposium.
Risk of psychosis was elevated for those who used the drug when they were young, the Dunedin Longitudinal Study showed, but not at the levels of that gene combination.
For people who used cannabis heavily before the age of 18, the risk of schizophrenia increased by 10.3 per cent, Poulton said.
For those who used it heavily after 18 years-old, the risk increased by 4.7 per cent.
This year, and for the first time in New Zealand, Fairfax Media is partnering with the Global Drug Survey to help create the largest and most up-to-date snapshot of our drug and alcohol use, and to see how we compare to the rest of the world. http://www.stuff.co.nz/national/health/9453354/Cannabis-hikes-schizophrenia-risk