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What is marijuana?
Marijuana is a plant (cannabis). It is smoked in the form of cigarettes (called joints) made from the stems, leaves, and flowering tops of the dried plant. There are over 200 slang names for marijuana, including pot, weed, Mary Jane, gangster, or chronic. Marijuana is also used as hashish, the pressed resin (tarry substance) of the plant.

A chemical in the plant called THC changes a person's body chemistry. The chemical is absorbed through the lungs and goes into the blood. THC causes the brain to release a chemical that makes a person feel "high." THC stays in the body's organs for several days. Marijuana may be more potent than it used to be in the 60s and 70s. This can cause very serious health problems.

Marijuana can cause dependence. If you are dependent on a drug, you feel a need for the drug when it is stopped. If you crave the drug, or feel distressed without it, you are psychologically dependent. If you have bodily changes such as anxiety or insomnia when the drug is stopped, you are physically dependent.

What about medical marijuana?
THC may be used to help people with glaucoma, certain nerve disorders, severe pain, or nausea from chemotherapy. In these cases, a health care provider can legally prescribe a pill form of THC. This is legal in only a few states.

How does marijuana affect the body?
Brain: Marijuana changes your view of reality. It can cause trouble with memory and learning, and trouble thinking clearly and solving problems. It also causes loss of coordination and slows your ability to respond quickly. Marijuana use can cause memory and learning problems for weeks after you stop using it. Marijuana may precipitate psychosis in those who are vulnerable.
Emotions: Marijuana users are more likely to be depressed or anxious than nonusers. You may not be interested in life, work, family, and friends. Relationships get worse and job and school performance suffers.
Lungs: Marijuana smoke contains 50% to 70% more cancer-causing chemicals than tobacco smoke. Marijuana users inhale more deeply and keep the smoke in their lungs much longer than tobacco users. This increases the amount of tars and chemicals that build up in the lungs. And because marijuana smoke is not filtered, one joint is equal to 10 to 40 tobacco cigarettes. Marijuana smokers have more chronic coughs and lung infections than nonsmokers.
Heart: Marijuana can increase blood pressure and heart rate. The carbon monoxide inhaled can decrease the blood's ability to carry oxygen.
Immune system: THC can change the way the body fights infection and cancer.
Pregnancy: Smoking marijuana while pregnant can cause lasting effects on a child. The baby may not grow normally. The child can have more behavioral problems and problems with language, attention, and memory.
How long do the effects last?
Urine test results for marijuana generally show positive for several days after you use marijuana. For regular users, test results may show positive for several weeks or longer.

A treatment program will focus on staying away from drugs for the rest of your life. A health care provider or counselor can help you find ways to better handle stress and anxiety.