As lawmakers in some states legalize marijuana for adults and people with certain medical conditions, you may be confused about how safe it is.
But the science shows: Smoking marijuana on a regular basis can harm the developing teen brain. (See facts below.)
We still have a lot to learn about marijuana’s effects on health. But applying lessons from tobacco’s past and understanding what scientists have already learned about marijuana can help us break down the hype.
The Tale of Tobacco
In the 1920s, researchers first linked smoking cigarettes to cancer. In 1957, the nation’s top doctor—the U.S. Surgeon General—warned that cigarette smoking could cause lung cancer. In spite of this, until the 1970s, nearly half of adults in the United States smoked.1 Tobacco smoke was everywhere—restaurants, bars, airplanes, offices, and theaters.
Because of mounting scientific evidence, limits were placed on smoking in public. But it wasn’t until the mid-1960s (40 years after the lung cancer link was discovered!) that smoking rates began to significantly drop. From 1965 to 2011, rates for adults dropped 55 percent.2 For teens, from 1991 to 2011, the drop was 34 percent.3 Although these decreases are improvements, 480,000 people in the United States still die prematurely every year from smoking or secondhand exposure to smoke.4 In fact, tobacco, along with alcohol, is responsible for more drug-related diseases and deaths than all illegal drugs combined.5
Is Marijuana the Next Tobacco?
Legalizing marijuana will likely make it easier to get and may increase the number of people who use it. But its use may also decline over time, as it did with tobacco, if people fully understand its harmful effects.
However, fewer young people now think marijuana is harmful than in the past.6 So how harmful is marijuana for teens? The science has a lot to say.
SCIENTIFIC FACTS ABOUT MARIJUANA
- Long-term, regular use of marijuana—starting in the teen years—may impair brain development and lower IQ, meaning the brain may not reach its full potential.7
- Decision making, memory, and concentration can suffer for days, after use, especially in regular users.8
- The risk for marijuana addiction almost doubles for people who begin using as teens (16 percent vs. 9 percent).9 Daily use increases the risk to about 25–50 percent.10
- Risk for addiction depends on a person’s genes, as well as his or her environment (social, economic, and emotional) and age. The younger the starting age, the greater the chances of addiction.
- For teens, frequent use of marijuana is linked to higher dropout rates9, poorer grades10, and driving accidents.11
- For adults, continued regular use is linked to financial struggles, unemployment, and life dissatisfaction.12
Other Drug Use
- Teens who use marijuana are more likely to use other drugs and develop drug problems compared with teens who don’t. Researchers don’t yet know if this is because of changes to the brain caused by marijuana or if it’s because marijuana smokers may hang out with people who also use other drugs.
Possible Increased Risk for Mental Disorders
- Marijuana use in adolescence has been linked to anxiety, depression, and schizophrenia, but scientists don’t yet know whether it directly causes these diseases.
ALERT: HASH OIL
- The honey-like resin from the marijuana plant has three to five times more THC (the main active ingredient in marijuana) than the plant itself. Smoking it (also called “dabbing”) can lead to dangerous levels of intoxication requiring emergency treatment. Fire Warning! People have been burned in fires and explosions caused by attempts to extract hash oil using butane (lighter fluid).
Lessons From Tobacco: Back to the Future
If you want to understand how attitudes can change with facts, take a look at tobacco.
Click on the timeline image to enlarge:
More Info on Marijuana: teens.drugabuse.gov/blog/mj
2,3 CENTERS FOR DISEASE CONTROL AND PREVENTION.
4 OFFICE OF THE SURGEON GENERAL.
5 THE LANCET.
6 MONITORING THE FUTURE.
7 BRAIN: A JOURNAL OF NEUROLOGY and PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. 8 JOURNAL OF ADDICTION MEDICINE.
9 THE LANCET.
10 W.D. HALL & R.L. PACULA.
11 ADDICTION JOURNAL and AMERICAN JOURNAL OF EPIDEMIOLOGY.
12 ADDICTION JOURNAL.
13 WORLD HEALTH ORGANIZATION.
Photos: ad with doctor, courtesy of Gaslight; ad with woman, © Illustrated London News Ltd/Mary Evans; x-ray, © Snoofek/Thinkstock; warning label, © Krista Kennell/Sipa Press/AP Photo; no-smoking symbol, © Racha Maysaluk/123RF.