Amphetamine, dextroamphetamine, methamphetamine, and their various salts, are collectively referred to as amphetamines. In fact, their chemical properties and actions are so similar that even experienced users have difficulty knowing which drug they have taken.

Amphetamine was first marketed in the 1930s as Benzedrine® in an over-the-counter inhaler to treat nasal congestion. By 1937, amphetamine was available by prescription in tablet form and was used in the treatment of the sleeping disorder, narcolepsy, and the behavioral syndrome called minimal brain dysfunction, which today is called attention deficit hyperactivity disorder (ADHD). During World War II, amphetamine was widely used to keep the fighting men going and both dextroamphetamine (Dexedrine®) and methamphetamine (Methedrine®) were readily available.

As use of amphetamines spread, so did their abuse. In the 1960s, amphetamines became a perceived remedy for helping truckers to complete their long routes without falling asleep, for weight control, for helping athletes to perform better and train longer, and for treating mild depression. Intravenous amphetamines, primarily methamphetamine, were abused by a subculture known as "speed freaks." With experience, it became evident that the dangers of abuse of these drugs outweighed most of their therapeutic uses.

Increased control measures were initiated in 1965 with amendments to the federal food and drug laws to curb the black market in amphetamines. Many pharmaceutical amphetamine products were removed from the market including all injectable formulations, and doctors prescribed those that remained less freely. Recent increases in medical use of these drugs can be attributed to their use in the treatment of ADHD. Amphetamine products presently marketed include generic and brand name amphetamine (Adderall®, Dexedrine®, Dextrostat®) and brand name methamphetamine (Desoxyn®). Amphetamines are all controlled in Schedule II of the CSA.

To meet the ever-increasing black market demand for amphetamines, clandestine laboratory production has mushroomed. Today, most amphetamines distributed to the black market are produced in clandestine laboratories. Methamphetamine laboratories are, by far, the most frequently encountered clandestine laboratories in the United States. The ease of clandestine synthesis, combined with tremendous profits, has resulted in significant availability of illicit methamphetamine, especially on the West Coast, where abuse of this drug has increased dramatically in recent years. Large amounts of methamphetamine are also illicitly smuggled into the United States from Mexico.

Amphetamines are generally taken orally or injected. However, the addition of "ice," the slang name for crystallized methamphetamine hydrochloride, has promoted smoking as another mode of administration. Just as "crack" is smokable cocaine, "ice" is smokable methamphetamine. Methamphetamine, in all its forms, is highly addictive and toxic.

The effects of amphetamines, especially methamphetamine, are similar to cocaine, but their onset is slower and their duration is longer. In contrast to cocaine, which is quickly removed from the brain and is almost completely metabolized, methamphetamine remains in the central nervous system longer, and a larger percentage of the drug remains unchanged in the body, producing prolonged stimulant effects. Chronic abuse produces a psychosis that resembles schizophrenia and is characterized by paranoia, picking at the skin, preoccupation with one's own thoughts, and auditory and visual hallucinations. These psychotic symptoms can persist for months and even years after use of these drugs has ceased and may be related to their neurotoxic effects. Violent and erratic behavior is frequently seen among chronic abusers of amphetamines, especially methamphetamine.

Stimulants, sometimes referred to as "uppers," reverse the effects of fatigue on both mental and physical tasks. Two commonly used stimulants are nicotine, which is found in tobacco products, and caffeine, an active ingredient in coffee, tea, some soft drinks, and many non-prescription medicines. Used in moderation, these substances tend to relieve malaise and increase alertness. Although the use of these products has been an accepted part of U.S. culture, the recognition of their adverse effects has resulted in a proliferation of caffeine-free products and efforts to discourage cigarette smoking.

A number of stimulants, however, are under the regulatory control of the CSA. Some of these controlled substances are available by prescription for legitimate medical use in the treatment of obesity, narcolepsy, and attention deficit disorders. As drugs of abuse, stimulants are frequently taken to produce a sense of exhilaration, enhance self esteem, improve mental and physical performance, increase activity, reduce appetite, produce prolonged wakefulness, and to "get high." They are among the most potent agents of reward and reinforcement that underlie the problem of dependence.

Stimulants are diverted from legitimate channels and clandestinely manufactured exclusively for the illicit market. They are taken orally, sniffed, smoked, and injected. Smoking, snorting, or injecting stimulants produce a sudden sensation known as a "rush" or a "flash." Abuse is often associated with a pattern of binge use--sporadically consuming large doses of stimulants over a short period of time. Heavy users may inject themselves every few hours, continuing until they have depleted their drug supply or reached a point of delirium, psychosis, and physical exhaustion. During this period of heavy use, all other interests become secondary to recreating the initial euphoric rush. Tolerance can develop rapidly, and both physical and psychological dependence occur. Abrupt cessation, even after a brief two- or three-day binge, is commonly followed by depression, anxiety, drug craving, and extreme fatigue known as a "crash."

Therapeutic levels of stimulants can produce exhilaration, extended wakefulness, and loss of appetite. These effects are greatly intensified when large doses of stimulants are taken. Physical side effects, including dizziness, tremor, headache, flushed skin, chest pain with palpitations, excessive sweating, vomiting, and abdominal cramps, may occur as a result of taking too large a dose at one time or taking large doses over an extended period of time. Psychological effects include agitation, hostility, panic, aggression, and suicidal or homicidal tendencies. Paranoia, sometimes accompanied by both auditory and visual hallucinations, may also occur. Overdose is often associated with high fever, convulsions, and cardiovascular collapse. Because accidental death is partially due to the effects of stimulants on the body's cardiovascular and temperature-regulating systems, physical exertion increases the hazards of stimulant use.