“Pot” and the Developing Teen Brain

Dr Michael Bradley is one of my favourite authors on parenting teens.  Check out his book, Yes, Your Teen is Crazy.  I’d like to share his most recent newsletter.


I do hate to be the bearer of scary news but there are a few new things you should know about marijuana. You know, that non-addicting, not-really-a-drug, “thank-God-he-only-does-weed” substance that this nation is about to decriminalize and perhaps even legalize over the next few years. “Eric,” the nice kid who just left my office, seemed to summarize all those views when he said, “I don’t get why you worry about my weed use. God put it on earth to end wars, you know. It’s, like, a one-hundred-percent natural herb. How could it be bad?” I wanted to respond, “You mean just like heroin?” but I knew the timing wasn’t quite right. Because when I try to show kids such as Eric the new science on weed and its impact on fragile, developing teen brains, they reflexively dismiss it as “right-wing-Christian-extremist-drug-cartel-government-sponsored propaganda.” And how do you respond to that?

What science do I try to show them? Well, one example is research coming from the Harvard Medical School (you know, that bastion of “right-wing-Christian-extremist-drug-cartel-government-sponsored propaganda.”) That study, presented at the Society for Neuroscience meeting in San Diego a few weeks ago, shows people who start using marijuana as teens have substantial cognitive shortfalls as adults. It also showed that the more marijuana a person used in adolescence, the more trouble they had with focus and attention as adults.

“Early onset smokers have a different pattern of brain activity, plus got far fewer correct answers in a row and made way more errors on certain cognitive tests,” says study author Staci Gruber, assistant professor of psychiatry at Harvard Medical School. “Our results provide further evidence that marijuana use has a direct effect on executive function, and that both age of onset and magnitude of marijuana use can significantly influence cognitive processing,” says Gruber. “Given the prevalence of marijuana use in the United States, these findings underscore the importance of establishing effective strategies to decrease marijuana use, especially in younger populations,” she says.

After reviewing Gruber’s data, Frances Jensen, professor of neurology at Children’s Hospital Boston (another extremist hotbed) noted, “There’s a myth that teen brains will bounce back, that they are really resilient, but in fact they may not be. It appears that they may be more vulnerable to drug use.” While a young brain is more “plastic” and able to learn, it can “maladapt” to the powerful and apparently permanent effects of weed, says Jensen. Virtually all recent studies (those measuring the impacts oftoday’s weed which is 3 to 9 times as potent as the old weed) show similar findings.

“So, OK,” Eric would concede, “maybe it can make you kinda’ stupid sometimes, but no way anyone gets addicted to weed.” Really!? Survey results released two weeks ago by The Partnership at Drugfree.org and MetLife Foundation found that marijuana use – particularly heavy use – has increased dramatically among U.S. high school students from 2008 to 2011. The Partnership Attitude Tracking Study found that 9 percent of teens (nearly 1.5 million) smoked marijuana heavily (at least 20 times) in the past month. Heavy marijuana use is up 80 percentamong U.S. teens since 2008. This corresponds frighteningly with other research showing that kids who start regularly using addictive substances (drugs or alcohol) at age 14 have at least afive-hundred-percent increased risk of addiction over those who do not use until ages 20 to 22 (the age at which most of the teen brain re-wiring seems to finish up). So, yes, weed is a dangero us teen drug, one that explodes in use with the advent of summer, just like the other weeds. So get ready for the fight.

How much weed use is OK for your kid? My answer is none. I understand that many teen experts advocate a laid-back view of pot smoking, pointing out that the great majority of kids eventually moderate use on their own, and these experts worry that adopting a zero-tolerance policy can lead to great conflicts with teens. I hold that if even just five percent of these kids don’t moderate, and do become addicts, then those odds are unacceptable. If your kid asked to ride a roller coaster that essentially took the life of every twentieth rider, would you be, like, “cool” with that?

So share the science with your teen now, and with his siblings starting at age 8 (that is not a misprint). Let them know early on that weed (like alcohol) is NOT the harmless right-of-passage drug as our culture portrays. Your calm, loving and unwavering objection to their drug use will have a profound safety effect in causing them to limit or entirely avoid drug use, especially if you start and end each conversation with, “Sorry, but I love you far too much to be ‘cool’ with things that can take your life.”  Things like the weeds of summer.

Dr. Mike Bradley
Dr. Mike Bradley

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