No amount of marijuana is safe for teens

“Since the failed war on drugs began more than 50 years ago, the prohibition of marijuana has ruined lives, families and communities, particularly communities of color,” House Minority Leader Hakeem Jeffries (D-N.Y.) recently said while announcing a bipartisan bill to legalize cannabis that the federal level. Jeffries added that the bill “will lay the groundwork to finally right these wrongs in a way that advances public safety.”  

But the growing body of evidence on cannabis’s effects on kids suggests this is not true at all.  

Cannabis legalization efforts across the U.S. have greatly accelerated over the last 15 years. Despite some recent success at anti-legalization efforts (e.g., Florida and North Dakota voters rejected in 2024 an adult use bill), the widespread public support for cannabis reform has translated to nearly half of U.S. states permitting adult use of cannabis, and 46 states with some form of a medical cannabis program. 

Though all legal-marijuana states have set the minimum age at 21, underage use has become a significant health concern. National data indicate that in 2024, 16.2 percent of 12th graders reported cannabis use in the past 30 days, and about 5.1 percent indicated daily use. To compound matters, product potency levels of the main intoxicant in the cannabis plant, THC (or Delta-9), have skyrocketed, from approximately 5 percent in the 1970s to upwards of 95 percent in THC concentrate products today. Even street-weed is routinely five to six times more potent than it was back in the day. 

The pro-cannabis landscape has likely moved teen perceptions of cannabis use. A prior encouraging trend of the 1970s and 1980s, when more and more teens each year perceived use of cannabis to be harmful, is now in reverse. Only 35.9 percent of 12th graders view regular cannabis use as harmful, compared to 50.4 percent in 1980. 

This is happening even as research is showing that cannabis is more deleterious to young people than we previously believed.  

The negative effects of cannabis use on a teenager can be seen across a range of behaviors. Changes may be subtle at first and masked as typical teenage turmoil. But ominous signs can soon emerge, including changes in friends, loss of interest in school and hobbies, and use on a daily basis. The usual pushback against parental rules and expectations becomes anger and defiance. For many, underlying issues of depression and anxiety get worse.

And there is a vast body of scientific research indicating that teen-onset use of THC use significantly increases the risk of addiction and can be a trigger for developing psychosis, including schizophrenia.

The pro-cannabis trend is not occurring in a vacuum. Those entrusted with protecting the health and well-being of youth — parents, community leaders, policy makers — have dropped the ball on the issue. Policymakers tout exaggerated claims that THC is a source of wellness and safer than alcohol or nicotine. In some states, cannabis-based edibles are sold in convenience stores. Many parents have a rearview-mirror perception of cannabis, as they assume the products these days are the water-downed versions from the 1960’s and ’70s.  

Aggravating matters are the influences of some business interests. The playbook from Big Tobacco is now being used by Big Cannabis: political donations, legislative lobbying, media support, and claims that solutions to social problems will follow legalization. 

The debate on the public health impact of legalizing cannabis will continue. We hope the discourse and policies will follow the science and give priority to the health and well-being of youth. An international panel of elite researchers on cannabis recently concluded that there is no level of cannabis use that is safe, and if use occurs, it’s vital to refrain until after puberty. The National Academy of Sciences and the National Institute on Drug Abuse also agree with these guidelines. One state — Minnesota — is requiring school-based drug prevention programs to include specific information on cannabis harms, a hopeful trend for other states to follow.

When recreational cannabis is made available to adults, perhaps we assume that legal restrictions to those age 21 and older is a sufficient guardrail. But history tells us that youth will indulge in adult-only activities. The pro-cannabis environment in the U.S. poses a public health challenge to young people. There isn’t a single challenge of being a teenager that cannabis will help solve. Sadly, this is a message that is not getting enough attention. 

Naomi Schaefer Riley is a senior fellow at the American Enterprise Institute, where she focuses on child welfare and foster care issues. Ken Winters is a senior scientist at the Minnesota branch of the Oregon Research Institute and is the co-founder of Smart Approaches to Marijuana Minnesota. This essay is adapted from a chapter in the forthcoming edited volume, “Mind the Children: How to Think About the Youth Mental Health Collapse.”