Pot-induced psychosis may signal schizophrenia

NEW YORK (Reuters Health) – People who have long-lasting psychotic episodes after smoking marijuana may be exhibiting early signs of schizophrenia, researchers reported Monday in the Archives of General Psychiatry.

“Cannabis-induced psychosis,” in which a person loses touch with reality and the symptoms persist for at least 48 hours, is an established psychiatric diagnosis, but it is controversial, Dr. Mikkel Arendt of Aarhus University in Risskov, Denmark, and colleagues note in their report. 

In a previous study, Arendt and colleagues found that nearly half of people who had an episode of cannabis-induced psychosis went on to develop schizophrenia within the next six years. In the current study, the researchers looked at the genetic roots of both conditions by comparing the family histories of 609 people treated for cannabis-induced psychosis and 6,476 who had been treated for schizophrenia or a related psychiatric condition.

They found that individuals treated for post-pot smoking psychotic episodes had the same likelihood of having a mother, sister or other “first-degree” relative with schizophrenia as did the individuals who had actually been treated for schizophrenia themselves. This suggests that cannabis-induced psychosis and schizophrenia are one and the same, the researchers note. “These people would have developed schizophrenia whether or not they used cannabis,” Arendt explained in comments to Reuters Health.

Based on the findings, the researcher says, “cannabis-induced psychosis is probably not a valid diagnosis. It should be considered schizophrenia.”

Even as we’ve complained that no data show that cannabis use causes schizophrenia, we’ve been told that for those who are genetically predisposed to schizophrenia, there seems to be a correlation between cannabis use and onset of psychotic symptoms.  So while it may not be psychologically dangerous for most of us, there is that 1% minority that would be harmed, so we have to ban it for everyone.

But this report counteracts even that claim.  In the conclusion of the report, the study authors note, “The degree of hereditary predisposition in individuals who receive treatment of cannabis-induced psychosis closely mirrors that in those who develop schizophrenia with no history of cannabis induced psychosis.”  This seems to tell us that when you take a look at a group of schizophrenics, whether they smoked pot of not, they still had the same genetic chances of becoming schizophrenics – the pot use didn’t matter!

Schizophrenia is rare and it comes on slowly for some.  This “cannabis-induced psychosis” is really just people in the beginning stages of schizophrenia who happen to smoke pot, and the pot is getting blamed.  It would be as valid to say the schizophrenic having an episode in a Krispy Kreme shop was suffering from “donut-induced psychosis”.

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