Drug addiction is a complex brain disease. It is characterized by compulsive, at times uncontrollable, drug craving, seeking, and use that persist even in the face of extremely negative consequences.
Drug seeking becomes compulsive, in large part as a result of the effects of prolonged drug use on brain functioning and, thus, on behavior.
For many people, drug addiction becomes chronic, with relapses possible even after long periods of abstinence.” (U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration)’