High-strength cannabis increases risk of mental health problems

Study says 30% of first-time psychotic disorders in south London linked to strong drugs
The Guardian (UK)
Tuesday, March 19, 2019

Frequent cannabis use and high-strength varieties are likely to increase the chance of mental health problems, according to researchers in the journal Lancet Psychiatry. Experts have previously flagged a link between cannabis use and psychosis. Now research suggests the potency of the cannabis is important, with patterns in cannabis use linked to how often new cases of psychotic disorders arise. The study estimated that 30% of first-time cases of psychotic disorders in south London, and half of those in Amsterdam, could be avoided if high-potency cannabis was not available. The study had limitations because it relied on self-reported use of cannabis and a small numbers of participants. Also, THC and CBD content of the cannabis was not directly measured. (See also: NORML responds to latest cannabis and psychosis claims)