The scientists found that treatment for up to 18 months in residential settings, or almost 14 months in outpatient nonmethadone treatment, yielded the greatest reductions in illicit drug use. Both overall and primary drug use declined after 18 months in long-term residential programs, at which point peak use measured about one-tenth the pretreatment level.
After 18 months in this setting, the amount of improvement began to wane. A similar effect was seen in people treated in nonmethadone outpatient settings. Individuals in nonmethadone programs who reduced drug use on their own before entering a treatment program were better able to remain in recovery.
The 4,005 patients in the study were treated for addiction to cocaine, heroin, or marijuana in 62 drug treatment units throughout the United States. As part of the National Treatment Improvement Evaluation Study, they were interviewed at admission, discharge, and one year after therapy ended between 1993 and 1995.
Treatment programs included methadone maintenance programs, outpatient nonmethadone programs, short-term residential programs, and long-term residential programs.
There was no significant relationship between treatment duration and overall drug use improvement for individuals in methadone maintenance and short-term residential programs.
Remaining in treatment for an extended time has beneficial outcomes for people in residential or outpatient drug treatment programs. Insurers may consider changing their policies to include a longer length of stay so people can be more effectively treated for their addictions.
Lead author Dr. Zhiwei Zhang of the National Opinion Research Center (NORC), a national organization for research at the University of Chicago, and his colleagues published this analytic study in the May 2003 issue of Addiction.
