In a January 21 opinion piece, Wall Street Journal columnist Allysia Finley sounded the alarm over the Department of Health and Human Services’ recent conclusion that “the risks to the public health posed by marijuana are lower compared to other drugs of abuse.”

HHS recommended that the Drug Enforcement Administration move marijuana from Schedule I (“no currently accepted medical use, and high potential for abuse”) to Schedule III (“low to moderate potential for physical and psychological dependence”). Examples of Schedule III drugs include codeine, testosterone, anabolic steroids, and ketamine. I have called for marijuana to be de-scheduled. But the ultimate decision rests with the DEA because, nowadays, cops practice medicine.

Ms. Finley points to reports of people who have had hallucinations and acute psychotic reactions when consuming marijuana. The same can occur when ingesting alcohol. Fortunately, these conditions are self-limited, and patients usually are treated and released from hospital emergency departments.

She also alludes to evidence of marijuana-induced chronic psychiatric problems. But, as I wrote here, most evidence of an association between marijuana use and chronic psychiatric problems is correlative. Researchers have not been able to find evidence of a causal relationship between the two.

Many countries saw stable or declining rates of psychosis between the 1960s and 1980s, a time when the number of people using marijuana in those countries increased dramatically. A 2003 Australian study found “no causal relationship” between cannabis use and schizophrenia, and a 2012 British study found rates of schizophrenia stable from 1950 to 2009, a time during which increasing numbers of people were consuming marijuana.

There is also a “chicken-or-egg” issue. For example, a 2018 meta-analysis found that genetic risk factors for cannabis use and schizophrenia are positively correlated. The meta-analysis applied bidirectional randomization and found a “consistent pattern of evidence supporting a causal effect of schizophrenia risk on lifetime cannabis use.” The study “found little evidence for any causal effect of cannabis use on schizophrenia.” 

A January 2022 article in the American Journal of Psychiatry illustrates the conundrum of correlation and causation.

To build her case against rescheduling marijuana, Ms. Finley points to research suggesting marijuana might have deleterious effects on developing brains in adolescents and teens, and maybe even on fetal brains. Of course, marijuana legalization advocates support legalizing the plant for adults, not for minors.

In response to the column, I wrote a letter to the editor of the Wall Street Journal. Unfortunately, the editor did not publish it. This is the letter:

Dear Editor:

Alysia Finley seems intent on bringing back “reefer madness” in her January 21 column “Marijuana is More Dangerous Than Biden’s HHS Lets On.” While acute cannabis-induced psychosis indeed exists, the cannabis-induced psychosis rate requiring emergency treatment is comparable to the rate of alcohol-induced psychosis, ranging from 0.4 to 0.7 percent of users, both of which are transient and self-limited. There is one difference, however: the DEA lists cannabis as a Schedule I drug (“no currently accepted medical use, and high potential for abuse”), whereas alcohol is not a scheduled drug at all. 

Unlike alcohol, cannabis does not suppress respiration, and there is no fatal overdose level. 

While Schedule I cannabis can cause cognitive impairment, non-scheduled alcohol is notorious for it. One recent study comparing alcohol, tobacco, and cannabis and the risk of traffic accidents showed it to be greatest with alcohol, while “the corresponding risk from tobacco use appeared to be almost as strong as cannabis use.” It also showed the “association between moderate cannabis use and psychosis is no stronger, and often considerably weaker, than the corresponding association for moderate tobacco use.” I should mention that tobacco is not a scheduled drug either, but it does have “a high potential for abuse.” 

No one disputes that cannabis, like alcohol and tobacco, can be harmful to young people, particularly children and adolescents. But, as with alcohol and tobacco, no one advocates that we legalize cannabis for minors. 

And if, like smoking tobacco and drinking alcohol, consuming cannabis while pregnant can harm the fetus, then health care practitioners should warn their pregnant patients about it. 

However, laws should not prohibit adults from consuming substances or engaging in activities simply because they are dangerous or harmful if children do them. If that were the case, lawmakers would bring back alcohol prohibition, completely ban tobacco products, completely ban gambling, and maybe even consider banning automobiles (many states let minors drive them and they are more likely to get in accidents than adults). 

In 2021, around 128 million people reported consuming cannabis at least once in their lifetime. A recent Gallup poll found 70 percent of Americans now support legalizing it. 

Unless Ms. Finley also wants to prohibit alcohol and tobacco, her arguments against moving cannabis off Schedule I are biased and inconsistent. 

Sincerely, 

Jeffrey A. Singer, MD

Senior Fellow, Cato Institute