While individuals progress through drug abuse treatment at different rates, one of the most reliable findings in treatment research is that lasting reductions in criminal activity and drug abuse are related to length of treatment. Generally, better outcomes are associated with treatment that lasts longer than 90 days, with treatment completers achieving the greatest reductions in drug abuse and criminal behavior. Again, legal pressure can improve retention rates.

A longer continuum of treatment may be indicated for individuals with severe or multiple problems. Research has shown that  treatment provided in prison and continued in the community after release can reduce the risk of recidivism to criminal behavior as well as relapse to drug use.

Early phases of treatment help the participant stop using drugs and begin a therapeutic process of change. Later stages address other problems related to drug abuse and, importantly, help the individual learn how to self-manage the drug problem. Because addiction is a chronic disease, drug relapse and return to treatment are common features of recovery. Thus, treatment may need to extend over a long period across multiple episodes of care.