Amphetamines are stimulants because they increase the activity of the nervous system. Amphetamines are sometimes called "uppers" because of the "wide awake" feeling people get when they take them.

People generally use amphetamines because they

• make them feel wide awake, energetic, confident, and talkative
• give people increased endurance and an enhanced ability to concentrate
• induce strong feelings of well-being and happiness

Other effects on behavior:

• loss of appetite
• difficulty sleeping
• jaw clenching and grinding of teeth
• feeling jittery and anxious

Common street names: Speed, uppers, meth, chalk, crank, crystal, ice, glass, dexies, black beauties, and whiz.

How are amphetamines taken? Amphetamines can be swallowed, snorted, smoked, or injected.

Risk of addiction: Very high risk

Effects on the body: Stimulation of the nervous system by amphetamines can cause

• increased heart rate
• increased breathing rate
• increased blood pressure
• increased body temperature
• sweating
• dehydration
• enlarged (dilated) pupils

Overdose: High doses of amphetamines have serious risks, including convulsions, high fevers, irregular heartbeat, coma, and possible death. Repeated use of amphetamines can lead to paranoid thinking, hallucinations, delusions, and violent and self-destructive behavior.

How are amphetamines produced? Amphetamines are synthesized in a laboratory. Some amphetamines are made illegally, while others are produced by drug companies for medical use.

Can amphetamines be used legally? Amphetamines are used legally in prescription drugs such as Adderall, Dexedrine, and an amphetamine-like drug called Ritalin. People use these prescription drugs for three main purposes:

• to help control weight in diet pills
• to treat excessive daytime sleepiness (narcolepsy)
• to treat hyperactive children with attention deficit disorders

Since amphetamines are stimulants, it may surprise you that they are used for treating hyperactive children. The reason for their usefulness seems to be simple. Amphetamines stimulate brain mechanisms that allow people to concentrate better, and this can have a calming effect on hyperactive children.

How long do amphetamines act? The effects of amphetamines generally last 4 to 6 hours. However, the length of time varies considerably, depending on the dose, type of amphetamine, and method used for administering the drug.

Drug tests for amphetamines: Amphetamines can be detected in the urine for up to 4 days after use.

How many students use amphetamines? About 7% of high school seniors say they have used some type of amphetamine within the past year.