Scientists say smoking high-potency marijuana every day could increase the chances of developing psychosis by about five times.
The new research adds to previous studies that have found links between marijuana and psychotic disorders, but it still does not definitively pinpoint marijuana as the cause.
Psychosis is usually triggered by factors like genetics and the environment. Experts say the new study's findings have implications for jurisdictions legalising marijuana, warning they should also consider the impact on their psychiatric services.
Experts analysed data from 11 sites across Europe and Brazil. They found daily marijuana use was more common among people with a new psychosis diagnosis than among those who didn't smoke pot.
Dr Marta Fiori, the study's lead author, said that people smoking high-potency marijuana should know psychosis is a potential risk.
