What You Aren’t Hearing About Marijuana’s Health Effects

Marijuana has much more serious health effects than is widely believed, according Bertha Madras, professor of psychobiology at Harvard Medical School. Allysia Finley has this interview in the WSJ, with the above title.

At one time, it was considered lots of fun to watch an absurd old propaganda film called Reefer Madness. But, ironically, we now know that there really is a connection between reefers and madness, i.e., schizophrenia.

There’s mounting evidence that cannabis can cause schizophrenia. A large-scale study last year that examined health histories of some 6.9 million Danes between 1972 and 2021 estimated that up to 30% of young men’s schizophrenia diagnoses could have been prevented had they not become dependent on pot. Marijuana is worse in this regard than many drugs usually perceived as more dangerous. “Users of other potent recreational drugs develop chronic psychosis at much lower rates,” Ms. Madras says. When healthy volunteers in research experiments are given THC—as has been done in 15 studies—they develop transient symptoms of psychosis. “And if you treat them with an antipsychotic drug such as haloperidol, those symptoms will go away.”

Prof. Madras thinks that the pending reclassification of marijuana from Schedule I to Schedule III “would be a colossal mistake.” “It’s a political decision, not a scientific one,” she says. “And it’s a tragic one.”