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Marijuana: Facts for Teens

Marijuana Fact: Most teenagers do not use marijuana.
Fewer than 1 in 5 high school seniors are current marijuana users.

Q: What is marijuana? Aren't there different kinds? A: Marijuana is a green, brown, or gray mixture of dried, shredded flowers and leaves of the hemp plant (Cannabis sativa). You may hear marijuana called by street names such as pot, herb, weed, boom, Mary Jane, gangster, or chronic. There are more than 200 slang terms for marijuana.

Sinsemilla (sin-seh-me-yah; it's a Spanish word), hashish ("hash" for short), and hash oil are stronger forms of marijuana.

All forms of marijuana are mind-altering. This means they change how the brain works. They all contain THC (delta-9-tetrahydrocannabinol), the main active chemical in marijuana. But there are also 400 other chemicals in the marijuana plant.

Q: How is marijuana used? A: Marijuana is usually smoked as a cigarette (called a joint or a nail) or in a pipe or a bong.

Recently, it has appeared in cigars called blunts which are larger and, therefore, more dangerous.

Q: How long does marijuana stay in the user's body? A: THC in marijuana is strongly absorbed by fatty tissues in various organs. Generally, traces (metabolites) of THC can be detected by standard urine testing methods several days after a smoking session. However, in heavy chronic users, traces can sometimes be detected for weeks after they have stopped using marijuana.

Q: How many teens smoke marijuana? A: Contrary to popular belief most teenagers have not used marijuana and never will. Among students surveyed in a yearly national survey, about one in six 10th graders report they are current marijuana users (that is, used marijuana within the past month). Fewer than one in five high school seniors are current marijuana users.

Q: Why do young people use marijuana? A: There are many reasons why some children and young teens start using marijuana. Most young people use marijuana because they have friends or brothers and sisters who use marijuana and pressure them to try it. Some young people use it because they see older people in the family using it.

Other users may think it's cool to use marijuana because they hear about it in music and see it used in TV and movies.

But no matter how many shirts and caps you see printed with the marijuana leaf, or how many groups sing about it, you should know this fact: You don't have to use marijuana just because you think everybody else is doing it. Most teens (four out of five) do not use marijuana!

Marijuana Fact: Marijuana can mess you up.
Your performance in school, sports and other activities will suffer if you're high.

Q: What happens if you smoke marijuana? A: The effects of the drug on each person depend on the user's experience, as well as:

  • how strong the marijuana is (how much THC it has);
  • what the user expects to happen;
  • the place where the drug is used;
  • how it is taken; and
  • whether the user is drinking alcohol or using other drugs.

Some people feel nothing at all when they smoke marijuana. Others may feel relaxed or high. Sometimes marijuana makes users feel thirsty and very hungry--an effect called "the munchies."

Some users can get bad effects from marijuana. They may suffer sudden feelings of anxiety and have paranoid thoughts. This is more likely to happen when a more potent variety of marijuana is used.

Q: What are the short-term effects of marijuana use? A: The short-term effects of marijuana include:

  • problems with memory and learning;
  • distorted perception (sights, sounds, time, touch);
  • trouble with thinking and problem-solving;
  • loss of coordination; and
  • increased heart rate, anxiety, panic attacks.

These risks are even greater when other drugs are mixed with the marijuana; and users do not always know what drugs are given to them.

Q: Does marijuana affect school, sports, or other activities? A: One of the biggest hazards of marijuana for teens is this: The drug can make you mess up in school, in sports or clubs, or with your friends. If you're high on marijuana, you are more likely to make stupid mistakes that could embarrass or even hurt you. If you use marijuana a lot, you could start to lose energy and lose interest in how you look and how you're getting along at school or work. In addition, there is a strong link between drug use and unsafe sex and the spread of HIV, the virus that causes AIDS.

Q: What are the long-term effects of marijuana use? A: Findings so far show that regular use of marijuana or THC may play a role in some kinds of cancer and in problems with the respiratory, immune, and reproductive systems.

  • Cancer. It's hard to know for sure whether regular marijuana use causes cancer. But it is known that marijuana smoke contains some of the same, and sometimes even more, of the cancer-causing chemicals as tobacco smoke. Studies show that 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.

  • Lungs and airways. People who smoke marijuana often tend to develop the same kinds of breathing problems that cigarette smokers have. They suffer frequent coughing, phlegm production, and wheezing, and they tend to have more chest colds than non-users.

  • Immune system. Animal studies have found that THC can damage the cells and tissues that help protect people from disease.

  • Reproductive system. Heavy use of marijuana can affect both male and female hormones. Young men could have delayed puberty because of THC effects. Young women may find the drug disturbs their monthly cycle (ovulation and menstrual periods).
Q: Does marijuana lead to the use of other drugs? A: Long-term studies of high school students and their patterns of drug use show that very few young people use other illegal drugs without first trying marijuana. Using marijuana puts children and teens in contact with people who are users and sellers of other drugs. So there is more of a risk that a marijuana user will be exposed to and urged to try more drugs. However, most marijuana users do not go on to use other illegal drugs.

Q: How can you tell if someone has been using marijuana? A: If someone is high on marijuana, he or she might:

  • seem dizzy and have trouble walking;
  • seem silly and giggly for no reason;
  • have very red, bloodshot eyes; and
  • have a hard time remembering things that just happened.

Marijuana Fact: Marijuana and driving do not mix.
Users often have delayed responses to sights and sounds drivers need to notice.

Q: How does marijuana affect driving? A: Marijuana has serious harmful effects on the skills needed for driving a car. Timing, coordination, alertness, and performance are all affected. For instance, the marijuana user may have trouble judging distances and may have delayed reactions to sights and sounds that drivers need to notice.

There are data showing that marijuana has played a role in crashes. A study of patients who had been in traffic accidents revealed that 15 percent of those who had been driving a car or motorcycle had been smoking marijuana, and another 17 percent had both THC and alcohol in their blood.

Q: Is marijuana sometimes used as a medicine? A: No. Under U.S. law since 1970, marijuana is a Schedule I controlled substance. This means that the drug, at least in its smoked form, has no commonly accepted medical use. THC that is manufactured into a pill can be used for treating the nausea and vomiting that occur with certain cancer treatments. The oral THC can be used to help AIDS patients eat more to keep up their weight, as well.

Q: If someone is pregnant and smokes it, will marijuana hurt the baby? A: Doctors advise pregnant women not to use any drugs because they could harm the growing fetus.

Some scientific studies have found that babies born to marijuana users were shorter, weighed less, and had smaller head sizes than those born to mothers who did not use the drug. Smaller babies are more likely to develop health problems. There are also research data showing nervous system problems in children of mothers who smoked marijuana.

Researchers are not certain whether a newborn baby's health problems, if they are caused by marijuana, will continue as the child grows.

Q: What does marijuana do to the brain? A: THC disrupts the nerve cells in the part of the brain where memories are formed. This makes it hard for the user to recall recent events, and so it is hard to learn while high. A working short-term memory is required for learning and performing tasks that call for more than one or two steps.

Some studies show that when people have smoked large amounts of marijuana for years, the drug takes its toll on mental functions. Researchers are still learning about the many ways that marijuana affects the brain.

Q: Can people become addicted to marijuana? A: Yes. While not everyone who uses marijuana becomes addicted, when a user begins to feel that he or she needs to take the drug to feel well, that person is said to be dependent or addicted to the drug. About 100,000 people seek treatment for marijuana use each year, showing they need help to stop using.

Some frequent, heavy users of marijuana develop a tolerance for it. "Tolerance" means that the user needs larger doses of the drug to get the same desired results that he or she used to get from smaller amounts.

Q: What if a person wants to quit using the drug? A: Up until a few years ago, it was hard to find treatment programs specifically for marijuana users.

Now researchers are testing different ways to help marijuana users abstain from drug use. There are currently no medications for treating marijuana dependence. Treatment programs focus on counseling and group support systems. There are also a number of programs designed especially to help teenagers who are abusers. Family doctors are also a good source for information and help in dealing with adolescent marijuana problems.

For more information on marijuana and other drugs, contact:

National Clearinghouse on Alcohol and Drug Information
P.O. Box 2345
Rockville, MD 20847
1-800-729-6686

National Institute on Drug Abuse
National Institutes of Health
U.S. Department of Health and Human Services

NIH Publication No. 98-4037
Printed 1995, Revised November, 1998

Feel free to reprint this publication in any quantity you wish.