Psychological dependency is addressed in many drug rehabilitation programs by attempting to teach the patient new methods of interacting in a drug-free environment. In particular, patients are generally encouraged, or possibly even required, to not associate with peers 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 culmination. For legal drugs such as alcohol, complete abstention—rather than attempts at moderation, which may lead to relapse—is also emphasized ("One is too many, and a thousand is never enough.") Whether moderation is achievable by those with a history of abuse remains a controversial point, but is generally considered unsustainable.