London, March 20 -- Smoking high-potency marijuana every day could increase the chances of developing psychosis by nearly five times, according to the biggest-ever study to examine the impact of pot on psychotic disorder rates.

The research adds to previous studies that have found links between marijuana and mental health problems, but still does not definitively pinpoint marijuana as the cause.

Psychotic disorders - in which people lose touch with reality - are typically triggered by factors including genetics and the environment. But experts say the new study's findings have implications for jurisdictions legalizing marijuana, warning they should consider the potential impact on their mental health services.

"If we think there's some...