Detoxification can take several days.
It is often required as withdrawal from alcohol and many drugs can be both uncomfortable and life threatening. Rehabilitation usually consists of individual counseling and several groups per day led by mental health professionals with specialized training in chemical dependency. Often these groups are in the 12-step style of Alcoholics Anonymous and Narcotics Anonymous. On staff there is usually a physician trained in psychiatry. Outpatient treatment can also be in the form of individual therapy.