Dazed and Confused: Is this what we want for our children?

On April 20, 2026, the largest U.S. study to date found that adolescent marijuana use was linked to diminished cognitive development. This study was done by researchers at the University of California, San Diego. It involved over 11,000 participants ages 9 to 10 whose cognitive abilities and substance use were tracked through ages 16 to 17.

Here are some notable findings of the study:

- Adolescents who used marijuana showed a lack of progress in thinking and memory skill development when compared to their peers who did not use marijuana.

- Modest decreases in cognition can translate into significant impacts. A decrease in learning and memory can impact testing, grade advancement, and higher education opportunities.  Visuospatial, memory skills, and processing speed decreases can have an impact on driving, which is already an area where teens inherently have disadvantages.

- Adolescents who use CBD for any reason still run the risk of being exposed to THC because product mislabeling is a known concern, even in regulated markets.

- It is important for adolescents/teens to avoid, or at least delay, marijuana use.

The last point of this study is particularly noteworthy. It is widely understood that marijuana use rewires underdeveloped brains (age 25 and below). This should be the most important data point for state marijuana legalization policies. Tying the legal age for marijuana consumption to mirror that of alcohol use (age 21) is nonsensical. All states must re-think current age limits for legal use.

While the University of California study focuses on cognitive development, it only adds to what is already known about youth marijuana use and health. Marijuana use can lead to psychosis, schizophrenia, depression, anxiety, heart issues, immune system depression, and a whole host of other ill effects that have life-long implications.

This study also underscores the concern that many adolescents and young adults do not view marijuana as a harmful substance. There are many reasons for this false belief. The primary among them being the continual push for marijuana normalization and legalization at the state level. Now that we are seeing the federal push to reclassify marijuana from a Schedule I to a Schedule III drug, this false perception that marijuana is harmless is only going to get worse.

The first line of defense to turn around the ongoing calamity of adolescent marijuana use is parental education. Parents are the critical factor in ensuring children have the right facts on marijuana and its negative health harms.

Parents: talk to your children today about the harms of high-THC products. Make sure they understand the risks and are wise to the hype being touted by the addiction-for-profit marijuana industry.

 You can read the full University of California study here: https://www.nature.com/articles/s41386-026-02395-1