Cannabis Alarmism Hinders Smart Regulations
Alex Berenson says he’s concerned there’s not enough research into cannabis risks, but his misleading arguments set scientists back.
Recent stories in major media outlets are raising the alarm that cannabis is “scary,” “dangerous,” and, amid a wave of states moving toward legalizing recreational use, “unstoppable.”
These dire warnings are coming from a new book titled “Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence” by Alex Berenson, a novelist and former journalist. Mr. Berenson’s central argument is that increased cannabis use is leading to higher rates of psychotic disorders and violence in the U.S. These claims are unfortunately misleading.
Cannabis, like all drugs, can cause harm. As states move toward legalizing recreational cannabis, there’s an argument to be made that we could be doing more to minimize the harms through regulations and public health interventions. But alarmist claims undermine efforts to improve regulation.
In one of his commentaries, Mr. Berenson cherry-picks quotes from a National Academies of Sciences, Engineering, and Medicine (NASEM) report to argue that cannabis causes psychotic disorders like schizophrenia. He cites this passage, “Cannabis use is likely to increase the risk of schizophrenia and other psychoses; the higher the use, the greater the risk.” But this sentence comes from a “highlights” portion of the report that does not reflect its final conclusion. While the report states there’s an association between cannabis and schizophrenia, it notes the “relationship between cannabis use and cannabis use disorder, and psychoses may be multidirectional and complex.”
There is, in fact, no basis for claiming that cannabis use has led to increased serious mental illness in the U.S.
A member of the report committee has publicly refuted Mr. Berenson’s claim that the report found a causal relationship between cannabis and schizophrenia. Put simply, correlation is not causation. Genetic risk factors may contribute to or mediate the association between cannabis use and schizophrenia. At the same time, cannabidiol, also known as CBD, may improve schizophrenia symptoms.
In the same article, Mr. Berenson points to increased prevalence of serious mental illness among 18-to-25-year-olds in recent years as proof that cannabis is fueling the rise of mental illness. But these increases appear to be driven by depressive episodes, not schizophrenia. The NASEM report only found moderate evidence associating cannabis use with a small increase in risk for depression. The report also found moderate evidence that major depressive disorder is a risk factor for cannabis use disorder, complicating any simple claims that increases in depressive episodes at the population level are driven by cannabis use.
There is, in fact, no basis for claiming that cannabis use has led to increased serious mental illness in the U.S. Washington and Colorado legalized recreational cannabis in 2012. The graphs below show that while cannabis use has increased in those states, rates of serious mental illness have not.