The Effects of Marijuana on the Teenage and Young Adult Brain

Many use marijuana for the mind-altering effects of tetrahydrocannabinol (THC), a naturally occurring, psychoactive compound found in certain species of the Cannabis plant family.1 In fact, cannabis (marijuana) is one of the most widely used substances in the United States. According to the 2021 National Survey on Drug Use and Health, 11.8 million young adults aged 18 to 25 reported using marijuana in the past year. In 2022, the Monitoring the Future Survey of middle and high school students found that 30.7% of 12th graders reported using marijuana in the past year, a number that remained consistent from the previous year but decreased from 2020.2 Of those 12th graders, 6.3% of them reported daily marijuana use.1

A colorful representation illustrates the chaotic and unpredictable effects of drugs on the developing teen brain.

Marijuana Use Among Teens and Young Adults

With a growing number of states legalizing marijuana for medicinal or adult recreational use, perceptions of the risks, benefits, and social acceptability associated with its use have changed—among adults and teens, too.3

Marijuana is the most widely used illegal drug among adolescents.3 Research suggests that such widespread use may reflect, at least in part, prevalent social norms amongst teen and young adults, the perceived risks and benefits of the drug, as well as frequent exposure to pro-marijuana messaging.3 Additionally, this group may use marijuana under peer pressure or to cope with stress, anxiety, even depression.4

Of the 52.5 million individuals aged 12 or older, who reported using marijuana in 2021, 35.4%—the largest percentage of all marijuana users—were young adults aged 18 to 25. Adolescents aged 12 to 17 accounted for 10.5% of that 52.5 million.5

Young people may use the dried flowers, leaves, stems, or seeds from the Cannabis plant, where marijuana derives, in several ways.1 They may smoke it in joints (hand-rolled cigarettes), in pipes or bongs (water pipes), or in blunts (emptied cigars filled with marijuana). They may inhale marijuana vapors, rather than smoke, by using a vaporizer or e-cigarette, as well as eat it after mixing it into brownies, cookies, or other edibles.1 Additionally, smoking or eating THC-rich resins that have been extracted from the cannabis plant have become increasingly popular methods of consumption.1

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