Researchers at the University of California San Diego have found that teenagers who start using cannabis show slower gains in memory, attention, and thinking skills over time than teens who do not use it. The findings were published in an April 2026 edition of Neuropsychopharmacology and were based on data from more than 11,000 participants in the Adolescent Brain Cognitive Development Study, the largest long-term investigation of brain development among young people in the United States.

Another study published in June of 2018 in JAMA Psychiatry supports these findings. That study showed that young people who used marijuana frequently were more likely to have lower scores on tests of memory, learning new information, and higher-level thinking involving problem solving and processing information.

With the legalization of marijuana, many people, including today’s youth, consider cannabis to be medicinal, natural, and not dangerous. Most consider it less addictive than many other illicit drugs and unlikely to create substantial impairment or behavior changes. Unfortunately, it is not without risks, and there are some important issues that parents of teenagers need to know:

• Increase in Potency. Decades ago, a typical joint contained less than 4 percent THC, the psychoactive compound in marijuana that causes the sensation of a high. Today, dried cannabis flower now averages closer to 15 to 20 percent THC. Additionally, today’s teens are much more likely to use high-potency products, such as THC-concentrated oils, vaping, edibles, waxes and crystals, which often contain anywhere from 40%-95% THC, an astronomical increase in potency that can have a significant impact on a developing adolescent brain.
• Change in Method. Decades ago, most marijuana users smoked a joint. That is rare now. Studies show that the most popular method of cannabis use is vaping. Research has shown that, compared with smoking cannabis, vaping increased the symptoms of short-term anxiety, paranoia, memory loss and distraction when doses were the same.

As marijuana has transformed in its potency and delivery method, the amount of THC a user receives has drastically increased. As a result, medical professionals are seeing increases in the number of people experiencing psychotic symptoms and/or addicted to marijuana. Teens are more vulnerable than adults to the impact of THC because their brain is still developing, which is likely why they are experiencing slower gains in memory, attention, and thinking than their sober peers.

It’s a good idea to talk to your adolescent children about cannabis and its risks, but you have to approach discussions with teens in a non-confrontational way for them to be effective. Conversations that aren’t loaded with strong beliefs or an emotional reaction let your teen know that you are open to hearing them and decrease the risk of an argument occurring. Be willing to listen and genuinely curious in order to prevent defensiveness. Avoid judgement and/or lectures. Decide ahead of time what you want your message to be and then be clear and consistent in stating it.

Final Thoughts…

Parents should not just discount marijuana use as harmless fun or as a “safer” drug. Parents who might have used a little bit of marijuana in college might be quick to think, “it’s just weed,” but it’s not that simple anymore. Be aware of the potential risks and inform your teen of the dangers.

It’s important for parents to continue talking to their children about the dangers of drug use, and to be able to talk about the most current trends. According to the Partnership for a Drug-Free America, teens are 50% less likely to use drugs if they learn about the risks of drug use from their parents. It’s important for trustworthy adults to provide teens with factual information. The facts both empower adolescents to make smarter decisions and give them the message that their families are open to answering their questions and providing assistance when they need it.