In recent years, abuse of methamphetamine has risen sharply in the United States, primarily because of the introduction of "crystal meth." Like other forms of methamphetamine, crystal meth is a stimulant that, in small doses, causes enhanced alertness and elevated energy. At higher doses, it can cause paranoid behavior, euphoria, sleeplessness and even profoundly self-destructive behaviors and psychosis. According to the U.S. Department of Justice, crystal meth use has increased dramatically in part because its underlying ingredients are relatively common -- they can be found in ordinary over-the-counter cold medicines as well as household and industrial chemicals -- and the drug can be "cooked" in small labs. However, there are not reliable data for the number of crystal meth users in the United States.

Because crystal meth is a higher potency than many commonly abused amphetamines, and because the drug frequently contains serious contaminants from its manufacturing process, the use of crystal meth is considered extremely dangerous. It is a highly addictive drug that causes extensive psychological and physical changes, including a rapid elevation of the heart rate and blood pressure, as well as damage to the blood vessels in the brain. Overdosing on crystal meth can cause heart attack and stroke.

While the drug is usually smoked, it can also be injected. This exposes the user to additional cardiac risks, including infection of the heart valves or lining, as well as HIV and hepatitis.