Amphetamine was first introduced in the 1930s as a remedy for nasal congestion. Later, all three drugs were found to be effective in treating such other conditions as hyperactivity in children and narcolepsy (uncontrollable sleeping fits). Although they were also prescribed to control obesity and depression, their use for these disorders has been discontinued because patients became quickly and seriously dependent.

The amphetamines have long been taken for their stimulant and euphoric effects. When they were easily available, truck drivers, students, and athletes were among those who used them extensively to prolong their normal periods of wakefulness and endurance.

Regular use of amphetamines induces tolerance to some effects, which means that more and more of the drug is required to produce the desired effects. Tolerance does not develop to all effects at the same rate, however; indeed, there may be increased sensitivity to some of them.

Chronic users may also become psychologically dependent on amphetamines. Psychological dependence exists when a drug is so central to a person's thoughts, emotions, and activities that the need to continue its use becomes a craving or compulsion. Experiments have shown that animals, when given a free choice, will readily operate pumps that inject them with cocaine or amphetamine. Animals dependent on amphetamines will work hard to get more of the drug.