Wednesday, July 10, 2019

MDs: The science isn't hazy (about pot)

(The following letter by doctors appeared in the Letter section of Globe & Mail newspaper, July 8, 2019)

The science isn't hazy

Cannabis industry advocates attempt to frame the link between cannabis and psychosis as debate (The Cannabis-Psychosis Debate Is Being Driven By Fear Mongering, Not Facts, July 1).

Unfortunately, the science is clear. The 2017 National Academy of Sciences Report says “there is substantial evidence of a statistical association between cannabis use and the development of schizophrenia and other psychoses, with the highest risk among the most frequent users.”

Cannabis use doubles the risk of developing psychosis with greatest risk to those genetically predisposed, use cannabis heavily, and/or experience paranoia with cannabis use. Cannabis users develop psychosis 2.7 years earlier than non-users. Psychosis from alcohol use is rare and psychosis is not caused by air contaminants or fatigue.

As cannabis use contributes to developing psychosis and can worsen psychosis, clinicians recommend not using or, at least, reducing cannabis to potentially minimize needing antipsychotic medication. Cannabidiol (CBD) for psychosis is preliminary with two of three randomized controlled trials showing no clinically significant benefit.

Reporting the science is not fear mongering, but it is our responsibility to highlight that psychosis is linked to cannabis use, especially high potency cannabis used daily or almost daily, starting in adolescence or young adulthood.
--David Crockford, Rob Tanguay, Wip Lambda, Charl Els and Phil Tibbo, MDs