Reduced Use of Illicit Opioids/Heroin

• Many studies conducted over a period of several decades in different countries have demonstrated clearly that MMT results in markedly decreased illicit opioid use (National Consensus Development Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1939).
• According to their review of the evidence, Hall et al. (1998b, 53) conclude that there is "strong evidence that there are substantial reductions in heroin use while [people who are dependent on opioids] are enrolled in methadone maintenance."
• Based on its review of the evidence, the National Institute on Drug Abuse (National Institute on Drug Abuse, 1995, 1-7) found that during MMT, clients'/patients' use of illicit opioids declines, sometimes "dramatically", but this requires adequate methadone dosage levels.
• MMT has moderate effect in reducing illicit opioid use (Marsch, 1998, Abstract).
• Based on their review of the evidence, Hall et al. (1998b, 53) conclude that "a number of caveats have to be entered to avoid unrealistic expectations of methadone maintenance treatment. First, methadone maintenance does not produce abstinence from all illicit opioids in all patients; nevertheless, it produces a substantial reduction in rates of heroin use and abstinence from illicit opioids in approximately half of those who receive it. Second, different programs differ in their effectiveness. Third, the best supported model of treatment is that developed by Dole and Nyswander, namely, opioid maintenance treatment. Fourth, accordingly, the benefits of methadone treatment continue only as long as clients/patients remain in treatment."
• Although achieving a sustained drug-free state is an "optimal treatment goal," the evidence indicates that this goal cannot be achieved by most individuals who are dependent on opioids (National Consensus Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1937).
• Based on an extensive review of the results of 11 randomized controlled trials and several observational studies, Ward, Mattick and Hall. (1998h, 217-222) indicate that there is a clear dose-response relationship between methadone dose and heroin use. The likelihood that clients/patients will use heroin decreases as the methadone dose increases.

Reduced Use of Other Drugs

• MMT programs "significantly and consistently" reduce the use of illicit opioids as well as the use of other illicit drugs, including cocaine and marijuana. MMT programs also reduce the abuse of alcohol, benzodiazepines, barbiturates, and amphetamines (National Consensus Development Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1939).
• Consistent with numerous previous evaluations of MMT, the Drug Abuse Treatment Outcome Studies (DATOS) found that MMT is effective in reducing illicit use of cocaine and other drugs (Fletcher & Battjes, 1999, 85).
• Based on its review of the evidence, the National Institute on Drug Abuse concluded that, research findings are "mixed" with regard to MMT's effect on the use of illicit drugs other than opioids. While some research indicates that MMT is associated with decreases in the use of alcohol, cocaine and marijuana, other research indicates increases in the use of these drugs. Although MMT does not have - is not intended to have - an effect on alcohol and other drug use, when the biopsychosocial treatment services included in MMT are "specifically designed to reduce alcohol and drug use, such reductions are likely." (National Institute on Drug Abuse, 1995, 4-15).
• Although methadone has no direct pharmacological effect on non-opioid drugs, when people who are dependent on opioids enter MMT their use of other drugs often declines (Lindesmith, 1997, 1).

• Over the past twenty years, the evidence from multiple studies has been "clear and convincing" in demonstrating that effective treatment of opioid dependence markedly reduces rates of criminal activity (National Consensus Development Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1939).
• Consistent with numerous previous evaluations of MMT, the Drug Abuse Treatment Outcome Studies (DATOS) found that MMT is effective in reducing the incidence of drug-related criminal behaviour (Fletcher & Battjes, 1999, 85).
• Based on their review of the evidence, Hall et al. (1998b, 53) conclude that there is "strong evidence that there are substantial reductions in crime while [people who are dependent on opioids] are enrolled in methadone maintenance."
• The effectiveness of MMT is most apparent in its ability to reduce drug-related criminal behaviours (Marsch,1998, Abstract).
• McGlothin and Anglin (as cited in National Institute on Drug Abuse, 1995, 4-8) found that MMT is associated with less time dealing drugs, less time involved in crime, and less time being arrested and incarcerated.
• MMT is associated with less time being arrested and incarcerated (National Institute on Drug Abuse, 1995, 4-8).
• Retention in treatment was found to have only a slight, but significant, effect on reducing criminal activity during treatment. More research is needed on "the dynamics of MMT in the 1990s and the relationship between crime and treatment" (Rothbard, Alterman, Rutherford, Liu, Zelinski, and McKay, 1999, 335).

• Studies have shown that death rates among individuals receiving methadone are lower than among those who are dependent on opioids and not receiving methadone treatment - the death rate for those not receiving treatment is more than three times higher than for those engaged in treatment (National Consensus Development Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1938).

• Consistent with numerous previous evaluations of MMT, the Drug Abuse Treatment Outcome Studies (DATOS) found that MMT is effective in supporting improvement in "several domains of health, mental health, and social function" (Fletcher & Battjes, 1999, 85).
• "Following entry into MMT, health status usually improves with access to medical care, elimination of injections with contaminated needles, and improved quality of life " (Lowinson et al., 1997, 409).
• Dole, Nyswander and Kreek (as cited in National Institute on Drug Abuse, 1995, 4-9) found that methadone maintenance treatment can stabilize the mood and functional state of clients/patients.
• Walsh and Strain (199, 50) note that there is "some evidence....that mehtadone and opioids in general can have anti-anxiety, antidepressant and anti-psychotic effects." They also point out, however, that controlled studies of the use of methadone for anxiety, depression or psychosis have not been done.
• Best, Lehmann, Glossop, Harris, Noble, and Strung (1998, 1) note that more research is needed on the effectiveness of methadone maintenance treatment that takes wider lifestyle variables (high smoking levels, poor diet and infrequent eating, and drinking) into account.

Reduced injection-related risk behaviours⁷

• A review of several studies indicates that MMT is consistently associated with reductions in sharing of drug injecting equipment, which is the main risk factor for transmission of blood-borne viruses such as HIV, hepatitis B and hepatitis C, among injection drug users. MMT reduces injection-related risk behaviour among injection drug users, but it does so only while clients/patients remain in treatment, and when they are receiving adequate doses of methadone (Ward, Mattick et Hall, 1998g, 67-68).
• Ball and Ross (as cited in National Institute on Drug Abuse, 1995, 4-22) found that 71% of clients/patients who remained in treatment for one year or more stopped injection drug use.
• MMT has a small to moderate effect in reducing HIV risk behaviours (Marsch, 1998, Abstract).

Reductions in other risk behaviours for HIV and other STDs

• Women who are dependent on opioids often support their drug use through sexual behaviour such as prostitution or exchanging sex for drugs. Because treatment "lessens the economic need for such sexual activity", MMT may be a potentially effective intervention for reducing sexual risk behaviour among women who are dependent on opioids (Wells, Calsyn et Clark, 1996, 519).
• MMT may help people who are dependent on opioids to reduce their risk of acquiring HIV through sex with multiple partners by reducing their involvement in sex work to support their drug habit and by increasing their "perceived self-efficacy for risk reduction" (Longshore, Hsieh et Anglin, 1994, 754).

HIV

• "Properly dosed, long-term methadone treatment was a central protective factor in preventing HIV infections from the earliest days of the epidemic in New York City "(Hartel & Schoenbaum, 1998, Abstract).
• Studies reviewed by Ward et al. (1998g, 64) show there is "reasonable support" to indicate that methadone maintenance protects clients/patients from HIV infection.
• "Methadone may protect against HIV....time spent in methadone treatment was the major determinant of remaining HIV-free" (Serpelloni, Carrieri, Rezza, Morganti, Gomma et Binkin, 1994, 218).
• Metzger et al.(as cited in National Institute on Drug Abuse, 1995, 4-19) found a lower rate of HIV infection among those receiving MMT (15%) compared to those who were dependent on opioids and not receiving treatment (33%). Those who remained out of treatment had a 22% increase in HIV seroconversion, compared to 3.5% for those in methadone maintenance treatment (in National Institute on Drug Abuse, 1995, 4-19, 4-20).

HCV and other blood-borne pathogens

• Dole, Joseph and Des Jarlais (as cited in National Institute on Drug Abuse, 1995, 4-23) found MMT was associated with reduced incidence of serum hepatitis.
• Current research reviewed by Ward et al. (1998g, 68-69) indicates that MMT is unlikely to protect clients/patients against infection with hepatitis B or C where the population of injection drug users has a high prevalence of hepatitis B and C. This is because clients/patients will usually have been exposed to hepatitis B and/or C by the time they present for treatment). At this time, there is insufficient evidence to evaluate the extent to which MMT can prevent hepatitis B and/or C infection.
• "The simple provision of methadone to [injection drug users] IDUs at risk of infection with or of transmitting HCV is not necessarily prophylactic against HCV transmission occurring." More assessment is needed to determine the role of MMT in prevention and control of transmission of HCV among IDUs (Crofts, Nigro, Oman, Stevenson et Sherman, 1997, 999).
• "Injection drug users not infected with HCV, who enter a methadone program and do not use other drugs or alcohol, are very likely to remain HCV negative (Novick, 2000, 440)."

Employment/Earnings/Social Productivity

• Consistent with numerous previous evaluations of MMT, the Drug Abuse Treatment Outcome Studies (DATOS) found that MMT is effective in supporting improvement in "several domains of health, mental health, and social function" (Fletcher & Battjes, 1999, 85).
• Long-term outcome data have shown that individuals who are dependent on opioids and who are in MMT earn more than twice as much money per year as those who are not in treatment (National Consensus Development Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1939).
• Simpson and Sells (as cited in National Institute on Drug Abuse, 1995, 4-18) found that MMT significantly increased the likelihood of being employed full-time.
• Gearing and Schweitzer (as cited in Brands & Brands, 1998, 2) found that two years after admission to methadone maintenance treatment, the percentage of clients/patients who became socially productive (defined as employed, in school or "homemaker") rose from 36% to 76%.

Quality of life

• Quality of life improves in most domains after one year in MMT (Dazord, Mino, Page et Broers, 1998, Abstract).

• Research has demonstrated that comprehensive MMT, combined with adequate prenatal care, decreases obstetrical and fetal complications (National Consensus Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1939).
• Preliminary data suggests that women who receive MMT are more likely to be treated with medication which reduces the rate of HIV transmission to their newborns (National Consensus Panel on Effective Medical Treatment of Opiate Addiction, 1998, 1939).
• According to a review by Ward, Mattick and Hall (1998d, 412), for many women who are pregnant and who are dependent on opioids, there is clear evidence that MMT is less harmful than either continued heroin use or detoxification.
• Based on the National Institute of Drug Abuse's review of the evidence, MMT reduces adverse pregnancy outcomes and reduces adverse birth outcomes (National Institute on Drug Abuse, 1995, 1-33).
• "Methadone has been shown to be an effective treatment for pregnant women who are using opioids (Jarvis & Schnoll, 1994, 160)."
• The work of Finnegan, Hagan and Kaltenbach, Silver et al., Kleber, and Woody et al. (as cited in Finnegan, 1991, 199) "show that when the physical, psychological, and sociological issues of pregnant opioid-dependent women and their children are coupled with MMT, the potential physical and behavioral effects of psychoactive drugs on the mother, the fetus, the newborn, and the child may be markedly reduced."

• Hubbard et al. (as cited in Brands & Brands, 1998, 2) found that MMT had substantially higher retention rates (68% after three months) compared to outpatient counselling without methadone (36%) or residential programs without methadone (45%).
• Retention rate was highest in MMT after one year (40%) compared to naltrexone (18%) and drug-free program (15%) (D'Ippoliti, Davoli, Perucci, Pasqualini and Bargagli, 1998, 167).