In addition to stopping drug use, the goal of treatment is to return the individual to productive functioning in the family, workplace, and community. Measures of effectiveness typically include levels of criminal behavior, family functioning, employability, and medical condition. Overall, treatment of addiction is as successful as treatment of other chronic diseases, such as diabetes, hypertension, and asthma.

Treatment of addiction is as successful as treatment of other chronic diseases such as diabetes, hypertension, and asthma.

According to several studies, drug treatment reduces drug use by 40 to 60 percent and significantly decreases criminal activity during and after treatment. For example, a study of therapeutic community treatment for drug offenders (See Treatment Section) demonstrated that arrests for violent and nonviolent criminal acts were reduced by 40 percent or more. Methadone treatment has been shown to decrease criminal behavior by as much as 50 percent. Research shows that drug addiction treatment reduces the risk of HIV infection and that interventions to prevent HIV are much less costly than treating HIV-related illnesses. Treatment can improve the prospects for employment, with gains of up to 40 percent after treatment.

Although these effectiveness rates hold in general, individual treatment outcomes depend on the extent and nature of the patient's presenting problems, the appropriateness of the treatment components and related services used to address those problems, and the degree of active engagement of the patient in the treatment process.