Addiction is defined as a chronic, relapsing disease, characterized by compulsive drug-seeking and drug use and by neurochemical and molecular changes in the brain. It is considered a brain disease because drugs change the brain's structure and functioning. These brain changes can be long-lasting and can lead to the harmful behaviors seen in people who abuse drugs.

Amphetamine is a collective term given to amphetamines, dextroamphetamines and methamphetamines. They are substances taken to boost energy, mood, and confidence, as well as to suppress appetite. Methamphetamines are the most powerfully addictive and can cause long-lasting damage to the brain and central-nervous system.

The drug is made easily in clandestine laboratories with relatively inexpensive over-the-counter ingredients. These factors combine to make methamphetamine a drug with high potential for widespread abuse.

Methamphetamine is commonly known as "speed," "meth," and "chalk." In its smoked form, it is often referred to as "ice," "crystal," "crank," and "glass." It is a white, odorless, bitter-tasting crystalline powder that easily dissolves in water or alcohol. It was developed early in the 20th century from its parent drug, amphetamine, and was used originally in nasal decongestants and bronchial inhalers. Methamphetamine causes increased activity, decreased appetite, and a general sense of well-being. Its effects can last six-to-eight hours. After the initial rush, there is typically a state of high agitation that in some individuals can lead to violent behavior.

Methamphetamine is a Schedule II stimulant, which means it has a high potential for abuse and is legally available only through a prescription. It is indicated for the treatment of narcolepsy (a sleep disorder) and attention-deficit/hyperactivity disorder; these medical uses are limited, and the doses are much lower than those typical among methamphetamine abusers.

We know that methamphetamine is structurally similar to the neurotransmitter dopamine, but it is quite different from cocaine. Although these stimulants have similar behavioral and physiological effects, there are some major differences in the basic mechanisms of how they work at the level of the nerve cell. However, the bottom line is that methamphetamine, like cocaine, results in an accumulation of the neurotransmitter dopamine, which appears to produce the stimulation and feelings of euphoria experienced by the user. In contrast to cocaine, which is quickly removed and almost completely metabolized in the body, methamphetamine has a much longer duration of action and a larger percentage of the drug remains unchanged in the body. This results in methamphetamine being present in the brain longer, which ultimately leads to prolonged stimulant effects. The actions of methamphetamine increase dopamine release while blocking its reuptake, leading to higher concentrations of dopamine, which can be deadly to the nerve terminals.

Methamphetamine comes in many forms and can be smoked, snorted, orally ingested, or injected. The drug alters moods in different ways, depending on how it is taken. People often ingest amphetamines by snorting them through the nostril initially. However, the level of absorption through this form of intake is not as predictable and rapid as injection or smoking.

Immediately after smoking the drug or injecting it, the user experiences an intense rush or flash that lasts only a few minutes and is described as extremely pleasurable. Snorting or oral ingestion produces euphoria—a high, but not an intense rush. Snorting produces effects within five minutes, and oral ingestion produces effects within 20 minutes. Smoking methamphetamine produces effects that can last for 12 hours or more.

As with similar stimulants, methamphetamine most often is used in a "binge and crash" pattern. Because tolerance for methamphetamine occurs within minutes—meaning that the pleasurable effects disappear even before the drug concentration in the blood falls significantly—users try to maintain the high by bingeing on the drug. In some cases, abusers indulge in a form of binging known as a "run," forgoing food and sleep while continuing abuse for up to several days.

Amphetamines. Last reviewed 12/31/1969
  • NIDA Research Report
  • DSM Made Easy: The Clinician's Guide to Diagnosis.
  • Substance Abuse and Mental Health Services Administration (SAMHSA). Office of Applied Studies