Overview: Speed is a common name for stimulant drugs, especially amphetamines. Speed exists today in two basic forms: prescription tablets and capsules or crystal meth, a crystalline powder which can be sniffed, ingested, smoked, or injected. In whatever form they take, stimulants cause similar effects in similar ways, by increasing arousal in the brain and central nervous system.

Appearance: Tablets, capsules, or white crystal powder with translucent rocks or chunks.

Street Names: Crystal, crank, meth, go-fast.

Actions/Effects: Speed acts in the brain by boosting levels of two neurotransmitters that regulate alertness and arousal: norepinephrine and dopamine. Besides elevating mood, speed also increases metabolism and blocks feelings of hunger and sleepiness. Still, overriding such basic drives cancels out the normal maintenance functions these drives serve, and most speed-related risks derive from the biological and psychological wear and tear that follows. Physical effects include increased heart rate, blood pressure, respiration, and body temperature. At high doses (or with long-term use), speed can cause paranoia and bizarre behavior.

Medical Uses: Because they reduce appetite, both amphetamines and amphetamine-like drugs (phentermine, phendimetrazine) are prescribed to treat obesity. Dexedrine® and other stimulants (Ritalin®, Cylert®) are used to treat attention-deficit disorder.

Risks/Side Effects: Anxiety, mood swings, and paranoia are common psychological effects of chronic use. With long-term use, symptoms intensify, and may involve paranoid delusions and hallucinations. Violent, self-destructive behavior is also common. Overdose can occur with all forms of speed. Symptoms include fever, convulsions, and coma. Death can result from aneurysms (ruptured blood vessels in the brain), heart failure, or high body temperature.

Duration: Depends on dose and user tolerance, but typically ranges 3-6 hours.

Trends: Amphetamine use has soared in recent years with the reemergence of crystal meth, and continuing high levels of use are reflected in various national surveys.

Demographics: Speed use is common among teens and young adults unaware of its reputation for trouble. Result? Many find out about problems the hard way: firsthand. Lifetime use by high school seniors in the class of 2006 stood at 12.4 percent, with 8.1 percent reporting use during the previous year. U.S. hospital emergency room admissions involving amphetamines totalled 138,950 during 2005.