Fact Check: Is Marijuana Legalization Hurting Teen Mental Health?
This article was originally published on Leafly.com and appears here with permission.
If you read this January 10 Wall Street Journal piece, you might conclude that a wave of cannabis-induced psychosis among teenagers is sweeping the country. The story highlights research on the correlation between cannabis use and conditions like schizophrenia and bipolar disorder. It suggests access to higher-potency cannabis is leading to ever-increasing rates of psychosis in teens.
But the actual data paints a different picture. Population studies of over 63 million people show that rates of psychosis do not go up amid legalization. Teen use rates of marijuana are actually going down. And our best science suggests that genetic factors—rather than cannabis use—are to blame for the correlation between cannabis and psychosis.
Can cannabis really induce life-long psychotic conditions—or is this yet another example of confusing correlation with causation, a common source of “reefer madness?”
Exploring Cannabis-Psychosis Links
The research on cannabis and psychosis is nuanced, but it definitely shows a strong correlation—as opposed to a causation—between the two. For instance, the data is clear that acute cannabis exposure can cause you to see vivid colors, or mis-hear sounds, or get anxious. These experiences have been described as transitory “psychosis-like” episodes—particularly for occasional users.
Confusing Correlation With Causation
With that in mind, it might not be surprising that when teens who use cannabis develop permanent psychosis-related conditions, their doctors and loved ones jump to the conclusion that cannabis caused the shift. There are numerous stories of teens who used cannabis and were subsequently diagnosed with these challenging, life-long conditions. Statistically, individuals who use cannabis are more likely to have bipolar disorder or schizophrenia than the general population.
But scientists have long struggled with the question of whether cannabis use actually causes these conditions—or if a third factor drives both. Based on cases where these conditions emerge after cannabis use, researchers estimate that cannabis-induced psychosis occurs in .0027% of consumers. But even at this exceptionally rare rate, correlative studies can’t prove whether cannabis is the cause of psychosis or not.
There are many ways to interpret the data that associate cannabis with psychosis. For example, individuals with psychosis conditions could be more likely to use cannabis in the first place, as a form of self-medication. If this were true, it would result in the same strong correlation.
Other Correlates: Alcohol, Tobacco
Cannabis certainly isn’t the only factor linked with psychosis, even though it receives …