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School Desk Blog: Marijuana Is Harmful for Adolescents

Marijuana Is Harmful for Adolescents

Marijuana is a controversial topic in Mendocino County. While some people tout marijuana as a wonder drug that cures everything from nausea to cancer, recent scientific studies show it can cause serious and lasting damage to the adolescent brain.

Just as science begins to unravel the dangers of marijuana for teens, those same teens interpret the legalization of marijuana in California as confirmation that marijuana is relatively safe.


A 2017 study by the American Academy of Pediatrics (AAP) notes that the concentration of tetrahydrocannabinol, or THC—the psychoactive substance in the marijuana plant—has increased from approximately 4 percent in the early 1980s to about 12 percent in 2012.

Locally, we’ve found teens with e-cigs or “pens,” vaping concentrations of THC of more than 70 percent. Obviously, the higher the concentration, the worse the health consequences. The AAP study also notes that the percentage of people likely to become addicted increases to 17 percent among those who initiate marijuana use in adolescence.


In addition to impaired short-term memory, the AAP study describes the consequences of using marijuana as “decreased concentration, attention span, and problem-solving skills, all of which interfere with learning.” It also notes that users under the influence suffer from altered motor control, coordination, judgment, reaction time, and tracking ability. Clearly, these skills are always good to have working well, but they are essential when operating a car. Just ask Ukiah Police Chief Chris Dewey about the statistics on impaired driving. They are terrifying.

Many local people believe marijuana is relatively harmless. Teens often think so, in part, because they are in the developmental stage of their lives when they think they are invincible. Parents of teens who may have smoked pot in the 1980s and ‘90s are sometimes using outdated information, judging marijuana/cannabis use on the potency they remember.


While short-term effects are damaging enough to turn away many potential users, longitudinal studies provide more cause for alarm. They’ve linked marijuana to mental health problems such as depression and psychosis. In addition, the AAP study says that “long-term marijuana use initiated in adolescence has negative effects on intellectual function and that the deficits in cognitive areas, such as executive function and processing speed, did not recover by adulthood, even when cannabis use was discontinued.”

To read the whole study, go to

It is important for our students to be able to attend school in a drug-free environment. This is more readily achieved through all of us working together to educate. Marijuana is not good for the adolescent brain. Science confirms this.

If you would like information about how to talk to your kids about cannabis, there are some great websites to review. The State of Colorado is a little ahead of California on this journey, so I recommend visiting the following websites: and (click on the Youth Prevention tab).

Teens can make better decisions when they’re armed with information. We all can.