Is marijuana linked to psychosis, schizophrenia? It’s contentious, but doctors, feds say yes

By June 28, 2020 Recent News

USA Today 31 January 2020
Our additional comment: If he remains off pot and symptom-free a year after the episode, the psychiatrist can say with certainty he suffered from “cannabis-induced psychosis.” “What shocked me is that I had never heard of it,” said McIntosh’s dad, Rob. “All you hear is all these proponents of legalization of pot without thought to the risks and the consequences.” In March, The Lancet, a British medical journal, reported a two to five times higher risk of psychotic disorders for daily consumers of high-THC marijuana compared with people who never used. 

A number of physicians and parents are pushing back against the long-held assertion of users and advocates that marijuana is a safe, benign and even beneficial drug.

Those sounding the alarm include the nation’s “mental health czar,” as well as doctors in Colorado, California and Massachusetts where marijuana is legal for recreational use. They say the facts are irrefutable: Excessive use of high-THC pot and concentrated oil is linked to psychotic episodes that in some cases develop into full-blown schizophrenia.

There is great disagreement over the strength of the science linking pot and psychosis. Advocates on either side of the marijuana debate have different interpretations of the connection reported in a National Academies cannabis study in 2017 and other studies. In March, The Lancet, a British medical journal, reported a two to five times higher risk of psychotic disorders for daily consumers of high-THC marijuana compared with people who never used.

Arguments surround how much of the illness is preceded or worsened by the drug use, how often marijuana is used in response to it and whether the psychosis would have occurred anyway.

“At the end of the day, you can’t make a causal statement,” said Ziva Cooper, research director of the UCLA Cannabis Research Initiative and a member of the National Academies panel. “You need to have some biological premise to show that this kind of exposure causes psychotic disorder.”

The federal government and other health officials say the type of psychosis McIntosh experienced and other psychiatric disorders are clearly tied to the drug.

“It is time for Americans to understand there are substantial risks with marijuana,” said Elinore McCance-Katz, the Department of Health and Human Services’ top mental health official. “This is not the government making up data.”