The following is excerpted from an online article posted by ScienceAlert.
Using cannabis raises the risk of teenagers developing a psychotic disorder by a staggering 11 times compared to teens who didn’t report using the drug, a Canadian study has found.
That’s a much stronger association than what previous studies have reported. A 2016 analysis of data from 10 different studies found the heaviest cannabis users were about four times more likely than non-users to be diagnosed with schizophrenia or another psychotic condition.
Part of the reason, aside from cannabis users’ age, is that much of the data used in past analyses of adolescent cannabis use comes from before 2000, when cannabis was far less potent than it is today, the team behind the new analysis suggests.
In this new study, McMaster University epidemiologist André McDonald and colleagues looked at formal diagnoses of a psychotic disorder, such as schizophrenia, rather than acute psychotic episodes or psychotic symptoms.
They also analyzed psychosis in late adolescence, as well as early adulthood, to make sure they weren’t missing (like other studies might have) a critical window when psychotic disorders tend to first appear.
The team linked survey data on cannabis use in teens and young adults, collected between 2009 and 2012, with public health records in Ontario, Canada, up to 2018. This allowed them to trace recorded diagnoses of psychotic disorders, such as schizophrenia, in the years after cannabis use among some 11,300 individuals.
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