Drug rehabilitation is an umbrella term for process of medical and/or psychotherapeutic treatment, for dependency on psychoactive substances such as alcohol, prescription drugs, and so-called street drugs such as cocaine, heroin or amphetamines. The obvious intent is to enable the patient to cease their previous level of abuse, for the sake of avoiding its psychological, legal, social, and physical consequences, especially in extreme abuse.
Many drug rehabilitation programs attempt to teach the patient new methods of interacting in a drug free method. In particular, patients are generally encouraged or required not to associate with friends who still use the addictive substance. Twelve-step programs encourage addicts not only to stop using alcohol or other drugs, but to examine and change habits related to their addictions. Many programs emphasize that recovery is a permanent process without a culmination. For legal drugs such as alcohol complete abstention rather than attempts at moderation, which may lead to relapse are also emphasized ("I don't want a drink, I want a hundred drinks.") Whether moderation is achievable by persons with a history of abuse remains a controversial point but is generally considered unsustainable.
Drug rehabilitation is sometimes part of the criminal justice system. People convicted of minor drug offenses may be sentenced to rehabilitation instead of prison, and those convicted of driving while intoxicated are sometimes required to attend Alcoholics Anonymous meetings.