The process by which an individual with a substance use disorder achieves an optimal state of health, psychological functioning and social well-being. Rehabilitation follows the initial phase of treatment (which may involve detoxification and medical and psychiatric treatment). It encompasses a variety of approaches including group therapy, specific behaviour therapies to prevent relapse, involvement with a mutual-help group, residence in a therapeutic community or half-way house, vocational training and work experience. There is an expectation of social reintegration into the wider community.