Practice Profile: Methadone Maintenance Therapy

Mattick and colleagues (2009) conducted a meta-analysis to evaluate the effectiveness of methadone maintenance treatment (MMT) on opioid dependence. Interventions were included in the review if they used MMT, including those that employed other treatments such as behavioral therapies or outpatient rehabilitation. Only randomized controlled trials of MMT were included. All studies had to compare MMT with either placebo maintenance or other non-pharmacological therapy for the treatment of opioid dependence. The authors conducted an electronic search, through December 2008, of several databases such as the Cochrane Central Register of Controlled Trials, PubMed, and Embase. Conference proceedings and reference lists of identified studies were reviewed, and authors of identified studies were asked about other published or non-published studies. The searches include non-English language literature (studies were translated if they met inclusion criteria).

A total of 11 studies were included in the review, which involved a total of 1,969 participants. All included studies were randomized controlled trials; two studies were placebo-controlled trials, and the remaining studies were not blinded. The duration of the studies varied, running from several weeks to 2 years. Three studies were conducted in a prison setting, and the other eight were conducted in medical or research facilities (such as outpatient hospital detoxification programs or community methadone treatment facilities). One study was conducted in Australia, one in Sweden, one in Hong Kong, and one in Thailand; the other seven studies were conducted in the United States. The age, gender, and race/ethnicity of participants varied by study. Most studies included only males or a majority of males. The average ages of participants ranged from 27 to 42 years. The race/ethnicity of participants in the U.S.-based studies included mostly white, Black, and Hispanic participants, with a smaller percentage of Native Americans and Asian/Pacific Islanders.

The outcomes of interest included heroin use (measured as morphine-positive urine or hair analysis), criminal activity, and mortality. The relative risks (RR) and 95-percent confidence intervals were calculated for dichotomous outcomes, and a standardized mean difference was calculated for continuous outcomes. The data were analyzed using a random effects model.

Egli and colleagues (2009) conducted a meta-analysis to evaluate the effects of drug prescription and substitution programs, including methadone maintenance treatment programs, on criminal behavior. Their comprehensive search included a keyword search of online abstracts, bibliographies, and literature databases (such as Campbell Crime and Justice Group (C2-SPECTR), National Criminal Justice Reference Service (NCJRS), MEDLINE, Harm Reduction Journal, Journal of Substance Abuse Treatment, National Treatment Agency for Substance Misuse (NHS), National Treatment Outcome Research Study (NTORS), Drug and Alcohol Dependence, and Drug and Alcohol Review).

Literature in any language, published after 1960, was eligible for inclusion in the meta-analysis. Studies related to any kinds of drugs were eligible, including drugs considered illegal according to international agreements and local (national) laws, such as heroin, morphine, opium, cocaine, crack, MDMA, amphetamines, LSD, ketamine, cannabis, fentanyl, and inhalants. However, only studies that met the following criteria were included: 1) randomized studies, quasi-experimental studies, and before-after comparisons that examined the effects of drug prescription and drug substitution programs on offending, which met level 4 or higher on the scale developed by Sherman and colleagues (1997); 2) interventions that were court-ordered or unrelated to any involvement with the criminal justice system; and 3) interventions based on substitution programs (e.g., methadone as a substitute for illegal drugs) rather than drug abstinence. Programs that did not include prescriptions for any treatment (e.g., psychotherapy, detoxification) or prescribed drugs such as tranquilizers or antibiotics were excluded. Studies that examined possible effects beyond offending (e.g., medical outcomes) were also not considered.

A total of 46 studies were identified; however, only 41 studies were eligible for inclusion in the meta-analysis. Of the 41 studies,10 studies (7 randomized controlled trials and 3 quasi-experimental designs) met level 4 or higher on the scale developed by Sherman and colleagues (1997) and were included in the meta-analysis. Study participants consisted of drug addicts, adults and adolescents, males and females. Of the 2,109 study participants included in the analysis, 1,025 were assigned to the treatment group and 1,084 to the control group. Control groups across these studies were assigned to wait-list, placebo, counseling, residential treatment, or detoxification groups. Program duration ranged from 2 months to 36 months.

Appropriate measures of the primary outcome for the review (criminal behavior) included offending, reconviction data, police records, and self-reported delinquency. Odds ratios and random and fixed effects models were calculated to measure program effects between the treatment and control groups.