Marijuana Use and Schizophrenia: The Missing Link

by Christina Bruni Patient Expert

In reality, there could be no link between marijuana use and developing schizophrenia. Critics contend that if there was a link, the number of people diagnosed with schizophrenia would have risen along with the increase in the use of marijuana over the decades. It went from an illicit drug craved by beatniks in the 1940s and 1950s, to a substance most teenagers have tried and that is popular among male teenagers.

Reefer Madness has gone from being a laughably funny propaganda movie to the central focus of research studies that attempt to link its use with the development of schizophrenia. For one such study Columbia researchers actively recruited people with schizophrenia to smoke pot even though they had never tried it before: Is this legitimate or even ethical? What exactly are the researchers trying to prove?

Cannabis use and psychotic symptoms are clearly linked.

What we do know from studies that were already conducted is that people with schizophrenia who smoke get an initial high like any other person who does not have the diagnosis, but like the 1970s song an hour later they're "one toke over the line" and the psychosis is in full-bloom.

So an argument can be made that schizophrenia patients are self-medicating. However if so, they don't realize the damage they're doing in the long run. Those of us diagnosed with schizophrenia who smoke pot require more hospitalizations, respond less well to medication and perform poorly on tests of memory and cognition. The culprit is THC: the chemical in marijuana that causes people in studies who ingested it to have psychotic symptoms.

Ironically: one study of bipolar patients and schizophrenia patients who smoked marijuana concluded that the mile-high bipolar crew performed better in a verbal fluency test than those with bipolar who did not smoke. This is not however a ringing endorsement for our bipolar friends to run out and light up.

A study conducted by Dr. Serge Sevy, an associate professor of psychiatry at the Albert Einstein College of Medicine in New York City, confirmed a link between cannabis use and the onset of schizophrenia. He studied 100 patients between the ages of 16 and 40 with schizophrenia. Half of this population smoked marijuana and among them 75 percent started smoking before the onset of their illness and their schizophrenia appeared about two years earlier than in those who did not use the drug.

Other factors disproved the link yet one thing was a determinant more than any other: gender alone predicted a large slice of the risk of early onset. 69 men and 31 women participated in the survey. Males typically become ill at or near age 19 and woman become sick at 22. Teenage boys are four times more likely than girls to be heavy pot smokers.

In one study led by Marie-Odile Krebs, professor of psychiatry at the National Institute of Health and Medical Research (INSERM) laboratory in France: a subgroup of 44 of 190 patients [121 who were cannabis users] developed schizophrenia within a month of first smoking pot and others saw their existing psychotic symptoms greatly worsen with each subsequent use of the drug. Their symptoms appeared three years earlier than the other cannabis users in the study.

The writer Maia Szalavitz in the original TIME article that explored this possible link suggested that "being at least somewhat socially connected is necessary to be able to obtain an illegal drug-if you appear too 'crazy,' people are less likely to befriend you and dealers may be too wary to sell to you." Also: some of our pot-smoking peers have better cognitive functioning than those of us who do not light up.

This is again not proof that we should run out and be on a first-name basis with the shady guy in apartment 9F who supplies dime bags. People with schizophrenia to a greater degree than the general public become addicted to marijuana.

Have no fear: ordinary burnouts have trouble maintaining.

I once knew a guy with no mental illness diagnosis to speak of [he simply had a character flaw] who was a daily pot smoker and couldn't get through a meeting without smoking a bowl beforehand. His brain was fried and he had no social graces and was fired from every job he ever obtained. He left a trail of jobs behind him longer than the list of social security numbers tapped into by an identity thief. He had no goal in life beyond driving to a house in Southeast Annadale and scoring weed every Saturday night. It goes without saying that he had numerous failed relationships too.

So: have I convinced you that marijuana and schizophrenia is a double threat for those of us with a diagnosis? In the early years of my role at the Connection I advised a couple of people who posted questions that such drug use could exacerbate symptoms in a person with a genetic risk for schizophrenia. This is not under debate.

It is also true that cannabis use would be a fine way to jeopardize your recovery.

Christina Bruni
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Christina Bruni

Christina Bruni wrote about schizophrenia for HealthCentral as a Patient Expert. She is a mental health activist and freelance journalist.