Turns Out Teens Know Smoking Kills, but They Don’t Know Jack About Weed

A survey finds that tobacco use is at a record low among young people—but less than half of high school seniors think marijuana is harmful.

Legalization of medical marijuana, and new laws in Washington and Colorado, appear to be sending the message that pot is safe. But the science says it's not, especially for young people. (Doug Menuez/Getty Images)

Apr 10, 2013· 3 MIN READ
Shari Roan is an award-winning health writer based in Southern California.

When it comes to teenagers and smoking, there’s some good news and some not-so-good news: The latest survey shows that teens get that tobacco is bad, but they don’t feel the same about pot. In fact, while tobacco use among adolescents is at a record low, the survey found more of them are smoking weed. According to the “Monitoring the Future” survey, just 44 percent of high school seniors think marijuana is harmful; that’s the lowest rate in four decades. And more than one-third of seniors said they’d tried pot in the last year.

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With medical marijuana legalized in 18 states, and two states—Colorado and Washington state—recently legalizing small amounts of marijuana for personal use, there’s a good chance that teens assume marijuana is safe, says Arthur Dean, chairman and chief executive of Community Anti-Drug Coalitions of America. “The perception of harm among young people is being significantly eroded,” he says. Similarly, says Dean, teens are less likely to think their parents and other people in their lives disapprove of pot use.

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So just how dangerous is it to use weed? That question is at the heart of every legalization campaign. Each side—pro and con—has no shortage of data to support its opinions. However, the evidence regarding the detrimental effects of marijuana on young people is more convincing than it is for adults. Studies show that smoking pot can hurt learning and memory—not a good thing for people who spend most of their waking hours in a classroom.

Specifically, research done at Duke University linked smoking weed to lower IQ. The study followed more than 1,000 people over several decades and recorded their marijuana use and IQ. Those who smoked regularly and who’d begun in adolescence had an average drop of eight IQ points by their 30s. “It does impact brain function and reduces one’s intellect. It has a tremendous impact on decision-making,” Dean says. “People make and become involved in more risky decisions—driving under the influence, taking chances relating to sexual activity. People are not as apt to make good, positive decisions under the influence of marijuana.”

Moreover, it’s now well-known that marijuana can trigger certain types of mental illness, such as psychotic illnesses, in people who are genetically vulnerable to those diseases. A recent study published by Israeli researchers in Comprehensive Psychiatry showed that people with mental illnesses are seven times more likely to smoke cannabis weekly compared to people without mental illness, and were ten times more likely to have a dependence or addiction to the drug. The authors are clear in noting that marijuana use among people with mental illness could be a form of self-medicating, to ease the pain of their illness. However, the drug could also worsen symptoms of the disease.

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And, it’s a myth that marijuana is not addictive, experts say. According to the Partnership at Drugfree.org, one survey found that more teenagers enter drug treatment programs each year with marijuana as the main substance they’re abusing, versus other types of drugs. In a 2004 study, 64 percent of teens admitted to treatment centers said pot was the main drug they abused. “It absolutely can be addictive,” stresses Dean. “What we find is if you start as a young adult, the chances of becoming addicted is about 10 percent, according to the National Institute on Drug Abuse. If you start in adolescence, around ages 12 to 14, that jumps to 17 percent. And, because it's more widely used, there are more people addicted to marijuana than all other drugs combined.”

The drug does not improve teenagers’ driving, either. A study reported by the National Highway Traffic Safety Administration found that even a moderate dose of marijuana can impair driving performance.

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Now some organizations are fighting back to bring teens a more cautionary message. The Catalyst Coalition, based in Northern California, has started an information campaign called “Be ahead of the crowd: Use your brain, not weed.” It’s based on a survey that showed between 31 percent and 47 percent of seventh-grade students in Napa County public schools said they believe that marijuana causes little or no harm if a person only smokes once or twice a week.

The campaign will include messages aired at local theaters and information sent home at school. The organizers are also collecting signatures on a petition aimed at the county’s board of supervisors that would declare pot harmful for teens, and encourage citizens to keep the drug out of their hands.

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The federal government's anti-drug campaign, “Above the Influence,” appears to be having some effect on lowering marijuana use by teens. A 2011 review of the program, which was launched in 2005, found those who had seen campaign messages were less likely to use pot.

States that have passed laws permitting marijuana use may be recognizing the need to keep the drug out of the hands of minors, Dean says. “We know the under-age drinking problems we have in America,” he says. “How are we going to prevent people under 21 from getting marijuana? [Law enforcement agencies] say they don’t have the necessary resources to combat this. People are starting to understand the challenges that come with legalization. Legalizing or making marijuana medicine, we believe, is bad policy. It’s bad public health policy. It doesn’t pass the common sense test.”

Why do you think there’s so much confusion about the potential health risks of marijuana?

Shari Roan is an award-winning health writer based in Southern California. She is the author of three books on health and science subjects.