Definition: Drug addiction involves compulsively seeking to use a substance, regardless of the potentially negative social, psychological, and physical consequences. Certain drugs, such as narcotics and cocaine, are more physically addicting than are other drugs. When you stop taking the drug, you may have unpleasant physical reactions.

Fact: An estimated 19.5 million Americans over the age of 12 use illicit (illegal) drugs. Many other people abuse or are addicted to legal substances. Marijuana is the most commonly used illicit drug. While not everyone who uses drugs becomes addicted, many people do. As many as 19,000 people die of drug-related causes every year.