Weed, chronic, skunk, or Mary Jane—no matter what it’s called, it’s still the same: marijuana. It’s the most popular illegal drug used by teens in the United States.

Five million teens in grades 7 through 12 have used marijuana in the last month, and 9.4 million have used it at least once in their lifetime, according to the Partnership for a Drug-Free America (PDFA) in New York City. It often seems like smoking marijuana is a normal part of teen life.

It might seem that way, but teen marijuana use has actually gone down, according to the 2000 Partnership Attitude Tracking Study, by PDFA. More teens are seeing weed for what it is: an illegal drug that has serious physical and psychological side effects.

Marijuana 101

What exactly is marijuana? This mind-altering drug is a green, brown, or gray mixture of dried, shredded leaves, stems, seeds, and flowers from the hemp plant (Cannabis sativa). There are about 400 chemicals in marijuana, but its main chemical, THC (delta-9-tetrahydrocannabinol), has the strongest effect on the brain.

Marijuana is usually rolled into a cigarette (“joint”) or put in a pipe. Other times, it’s mixed into food or tea. Some users smoke a “blunt,” an empty cigar that’s been filled with marijuana.

According to the National Institute on Drug Abuse (NIDA), in Bethesda, MD, marijuana, when smoked or ingested, makes users “intoxicated” or “euphoric,” and “engrossed with ordinary sights, sounds, or tastes.” After using weed, typical events may seem “extremely entertaining, interesting, or funny” to teens.

“When I first started smoking pot, I didn’t even believe that it could have any negative effects,” says Jason, 16, of Philadelphia, PA. “I’d never used drugs before and it made me feel so different than I thought I’d feel. I just felt so calm and good; I didn’t believe it was hurting my mind and body.”

Damage Done

Marijuana was hurting Jason’s mind and body. Users experience such short-term effects as memory and learning problems, distorted perceptions of sight, sound, time, and touch. They may also have trouble with thinking and problem solving, and experience a loss of coordination, increased heart rate, and anxiety, according to the NIDA. (These effects are even greater when marijuana is mixed with other drugs and alcohol.)

Marijuana smoke contains some of the same cancer-causing agents as tobacco, sometimes in higher concentrations. So teens who smoke marijuana may experience long-term lung problems later in life. (According to the NIDA, someone who smokes five joints per week may be taking in as many cancer-causing chemicals as someone who smokes a full pack of cigarettes every day.)

“Because of the drug’s effects on perceptions and reaction time, users may also become involved in risky sexual behavior,” says Barbara Delaney, director of research for the Partnership. “There is a strong link between drug use and unsafe sex and the spread of HIV, the virus that causes AIDS.”

More Problems

In addition to engaging in risky behavior, "some frequent, long-term marijuana users experience a loss of motivation," adds Delaney. “Their problems include not caring about what happens in their lives, no desire to work regularly, fatigue, and a lack of concern about how they look. As a result of these symptoms, some users tend to perform poorly in school or at work.”

That’s what Tyler, 17, of St. Louis, MO, witnessed in friends who used marijuana.

“I have friends who smoke pot to ’solve’ their problems, but it seems like smoking marijuana has caused them more, like a lack of motivation, no money, and doing worse in school,” he says.

Like Tyler, more teens are seeing the damage caused by marijuana, and turning away from the drug. The 2000 Partnership Attitude Tracking Study found that many teens now believe marijuana will make them “lazy,” “boring,” and “act stupidly or foolishly.”

They’re realizing that marijuana doesn’t solve problems—it only creates more.

Jenny Bickel, a Sex, Etc. ncontributor from St. Louis, MO, contributed to this story.

Editor's Note: For more information about marijuana or treatment referrals, contact:

• Partnership for a Drug-Free America, 1-212-922-1560.
• The National Clearinghouse for Alcohol and Drug Information, sponsored by the Substance Abuse and Mental Health Services Administration. 1-800-729-6686.