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Does Marijuana Lead to the Use of Other Drugs?

It could. 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. For example, the risk of using cocaine is much greater for those who have tried marijuana than for those who have never tried it. 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.

To better determine this risk, scientists are examining the possibility that long-term marijuana use may create changes in the brain that make a person more at risk of becoming addicted to other drugs, such as alcohol or cocaine. Further research is needed to predict who will be at greatest risk.

How Can You Tell if Someone has Been Using Marijuana?

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
• have a hard time remembering things that just happened

When the early effects fade, over a few hours, the user can become very sleepy.

Is Marijuana Sometimes Used as a Medicine?

There has been much talk about the possible medical use of marijuana. Under U.S. law since 1970, marijuana has been a Schedule I controlled substance. This means that the drug, at least in its smoked form, has no commonly accepted medical use.

THC, the active chemical in marijuana, is manufactured into a pill available by prescription that can be used to treat the nausea and vomiting that occur with certain cancer treatments and to help AIDS patients eat more to keep up their weight. According to scientists, more research needs to be done on THC's side effects and other potential medical uses.

How Does Marijuana Affect Driving?

Marijuana has serious harmful effects on the skills required to drive safely: alertness, the ability to concentrate, coordination, and the ability to react quickly. Marijuana use can make it difficult to judge distances and react to signals and sounds on the road.

Marijuana may play a role in car accidents. In one study conducted in Memphis, TN, researchers found that, of 150 reckless drivers who were tested for drugs at the arrest scene, 33 percent tested positive for marijuana, and 12 percent tested positive for both marijuana and cocaine. Data have also shown that while smoking marijuana, people show the same lack of coordination on standard "drunk driver" tests as do people who have had too much to drink.

If a Woman is Pregnant and Smokes Marijuana, Will it Hurt the Baby?

Doctors advise pregnant women not to use any drugs because they could harm the growing fetus. One animal study has linked marijuana use to loss of the fetus very early in pregnancy.

Other studies in children born to mothers who used marijuana have shown increased behavioral problems during infancy and preschool years. In school, these children are more likely to have problems with decision making, memory, and the ability to remain attentive.

Researchers are not certain whether health problems that may be caused by early exposure to marijuana will remain as the child grows into adulthood. However, since some parts of the brain continue to develop throughout adolescence, it is also possible that certain kinds of problems may appear as the child matures.

What Does Marijuana Do to the Brain?

Some studies show that when people have smoked large amounts of marijuana for years, the drug takes its toll on mental functions. Heavy or daily use of marijuana affects the parts of the brain that control memory, attention, and learning. A working short-term memory is needed to learn and perform tasks that call for more than one or two steps.

Smoking marijuana causes some changes in the brain that are like those caused by cocaine, heroin, and alcohol. Scientists are still learning about the many ways that marijuana can affect the brain.

Can People Become Addicted to Marijuana?

Yes. Long-term marijuana use can lead to addiction in some people. That is, they cannot control their urges to seek out and use marijuana, even though it negatively affects their family relationships, school performance, and recreational activities. According to one study, marijuana use by teenagers who have prior antisocial problems can quickly lead to addiction. In addition, some frequent, heavy marijuana users develop "tolerance" to its effects. This means they need larger and larger amounts of marijuana to get the same desired effects as they used to get from smaller amounts.

What if a Person Wants to Quit Using the Drug?

In 2001, over 255,000 people entering drug treatment programs reported marijuana as their primary drug of abuse. However, 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 addiction. Treatment programs focus on counseling and group support systems. There are also a number of programs designed especially to help teenagers who are abusers.

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