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This paper describes the political origins of the National Treatment Outcomes Research Study (NTORS) and the outputs and impacts of the study. NTORS was designed to meet the request of the Health Secretary and of a Government Task Force for evidence about the effectiveness of the national addiction treatment services. NTORS was a prospective cohort study which investigated outcomes over a 5-year period of drug users admitted to four major treatment modalities: in-patient treatment, residential rehabilitation, methadone reduction and methadone maintenance programmes. The study investigated treatments delivered under day-to-day operating conditions. Outcomes showed substantial reductions in illicit drug use and reduced injecting risk behaviours. These changes were accompanied by improved psychological and physical health and by reductions in criminal behaviour. However, not all outcomes were so positive. There was a continuing mortality rate in the cohort of about 1% per year, and many clients continued to drink heavily throughout the 5-year follow-up. NTORS findings informed and influenced UK addiction treatment policy both at the time and subsequently. The findings were influential in supporting an immediate increase in funding for treatment, and Government Ministers have repeatedly cited NTORS as evidence of the effectiveness of addiction treatment. One finding that received political attention was that of the cost savings provided by treatment through reductions in crime. This important finding led to an unanticipated consequence of NTORS; namely, the greater focus on crime reduction that has increasingly been promoted as a political and social priority for drug misuse treatment. [ABSTRACT FROM AUTHOR]

Background Opioid maintenance treatment (OMT) is associated with reduced crime among heroin users, but little is known about how crime changes during different phases of treatment. The aim of this study was to investigate changes in criminal convictions on a day-to-day basis before and after entry or discharge from OMT. Methods National cohort study of all patients (n = 3221) in OMT in Norway 1997-2003. Patients were followed over a 9-year period, before, during, and after treatment. Criminal convictions were studied on a day-to-day basis in relation to treatment status. A time-continuous estimate of the probability of convictions within the population for all days during observation was calculated. Results Changes in convictions were evident before changes of treatment status. During the 3 years prior to OMT, the convictions rate was approximately 0.4% per day. Prior to OMT, convictions decreased to about 0.2% per day on the day of treatment initiation. During the weeks before dropping out of treatment, convictions increased. The patterns during periods of transition were the same across gender, age and pre-treatment conviction-levels. Conclusions Changes in convictions often occurred prior to changes in treatment status. Reductions in criminal convictions were found in the period before entry (or re-entry) to OMT, and increases in criminal activity were found in the months prior to treatment interruption. [ABSTRACT FROM AUTHOR]

Aims Naltrexone is a competitive opioid antagonist that effectively blocks the action of heroin and other opioid agonists. Sustained-release naltrexone formulations are now available that provide long-acting opioid blockade. This study investigates the use of heroin and other opioids among opioid-dependent patients receiving treatment with long-acting naltrexone implants, their subjective experience of drug ‘high’ after opioid use, and factors associated with opioid use. Methods Participants ( n = 60) were opioid-dependent patients receiving treatment with naltrexone implants. Outcome data on substance use, drug ‘high’, depression and criminal activity were collected over a 6-month period. Blood samples were taken to monitor naltrexone plasma levels, and hair samples to verify self-reported opioid use. Findings More than half [ n = 34 or 56%; 95% confidence interval (CI) 44–68%)] the patients challenged the blockade with illicit opioids during the 6-month treatment period; 44% ( n = 26; 95% CI 32–56%) were abstinent from opioids. Mean opioid use was reduced from 18 [standard deviation (SD)13] days during the month preceding treatment to 6 days (SD 11) after 6 months. Of the respondents questioned on opioid ‘high’ ( n = 31), nine patients (30%; 95% CI 16–47%) reported partial drug ‘high’ following illicit opioid use, and three (12%; 95% CI 3–26%) reported full ‘high’. Opioid use was associated with use of non-opioid drugs and criminal behaviour. Conclusions Challenging naltrexone blockade with heroin on at least one occasion is common among sustained-release naltrexone patients, but only a minority of patients use opioids regularly. Challenges represent a warning sign for poor outcomes and often occur in the context of polydrug use and social adjustment problems. [ABSTRACT FROM AUTHOR]

This article reviews the main pharmacotherapies that are currently being used to treat opioid addiction. Treatments include detoxification using tapered methadone, buprenorphine, adrenergic agonists such as clonidine and lofexidine, and forms of rapid detoxification. In opioid maintenance treatment (OMT), methadone is most widely used. OMT with buprenorphine, buprenorphine-naloxone combination, or other opioid agonists is also discussed. The use of the opioid antagonists naloxone (for the treatment of intoxication and overdose) and oral and sustained-release formulations of naltrexone (for relapse prevention) is also considered. Although recent advances in the neurobiology of addictions may lead to the development of new pharmacotherapies for the treatment of addictive disorders, a major challenge lies in delivering existing treatments more effectively. Pharmacotherapy of opioid addiction alone is usually insufficient, and a complete treatment should also include effective psychosocial support or other interventions. Combining pharmacotherapies with psychosocial support strategies that are tailored to meet the patients’ needs represents the best way to treat opioid addiction effectively. [ABSTRACT FROM AUTHOR]

Background:After prison release, offenders with heroin use problems are at high risk of relapse and overdose death. There is a particular need for treatments that can be initiated in prison and continued after release into the community. Methadone maintenance treatment has been shown to reduce heroin use, criminality and mortality. Naltrexone implant treatment has not previously been evaluated in prison settings. Methods:This study compares the effects of naltrexone implants and methadone treatment on heroin and other illicit drug use, and criminality among heroin-dependent inmates after release from prison. Results:Forty-six volunteers were randomly allocated to naltrexone implants or methadone before release. Intention-to-treat analyses showed reductions in both groups in frequency of use of heroin and benzodiazepines, as well as criminality, 6 months after prison release. Conclusions:Naltrexone implants may be a valuable treatment option in prison settings. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aims This study investigates how age of opioid users is related to causes of death prior to, during and after opioid maintenance treatment (OMT), and estimates risks of death from various causes in relation to age. Design, setting and participants Data on all opiate dependents in Norway (1997–2003) who applied for and were accepted for OMT ( n = 3789) were cross-linked with the Norwegian death register. The total observation time was 10 934 person-years. Findings A total of 213 deaths was recorded. Of these, 73% were subject to autopsy, and causes of death were known for 208 cases: the overall death rate was 1.9%. Deaths were due to drug overdose (54%), somatic (32%) and traumatic causes (14%). Overdose deaths among all age groups were reduced during OMT but age had a differential effect upon risk when out of treatment. Younger opioid users were at greater risk of overdose before entering treatment; older users were at greater risk after leaving treatment. Older OMT patients were at higher risk of both somatic and traumatic deaths, and deaths during OMT were most likely to be due to somatic causes. Conclusions The high rates of overdose prior to and after treatment emphasize the need to provide rapid access to OMT, to retain patients in treatment and to re-enrol patients. The high prevalence among older patients of deaths due to somatic causes has implications for screening, treatment and referral, and may also lead to increased treatment costs. [ABSTRACT FROM AUTHOR]

Aims The present study represents the first large-scale test of the capacity to predict illicit drug treatment outcomes of an instrument [Stages of Change and Treatment Eagerness Scale (SOCRATES)] purporting to measure processes underlying stages of change. The main hypothesis was that ‘taking steps’ should be predictive of less frequent use of illicit opiates (heroin and non-prescribed methadone) at follow-up. Design The sample comprised 1075 people seeking treatment for drug abuse problems in 54 treatment agencies in England. The study uses a longitudinal, prospective cohort design. Structured interviews were conducted at treatment intake and at 1-year follow-up. Data were collected about illicit drug use (frequency of use of heroin, non-prescribed methadone, cocaine and amphetamines, and non-prescribed benzodiazepines) and other problems. Findings Results failed to support the hypothesis that taking steps should be associated with less frequent use of illicit opiates at follow-up. No statistically significant associations of any kind were found between readiness for change measures and use of opiates or stimulants at follow-up. A negative association was found between taking steps and benzodiazepine misuse. Readiness for change measures were correlated with heroin use and psychiatric symptom scores at treatment intake. Conclusions Readiness for change measures were not associated with illicit drug use outcomes. Of the 12 hypothesized relationships between readiness for change measures and outcomes, our results show only one ‘hit’ and 11 ‘misses’. [ABSTRACT FROM AUTHOR]

Aim To investigate the persistence of use of heroin, cocaine and amphetamine drugs during imprisonment, and to identify factors associated with increased levels of persistence. Design The use of heroin, cocaine and amphetamine by current prison inmates has been examined and, in particular, the relationship between drug use within prison and the type of drug used prior to imprisonment, recency of use and severity of dependence. Setting and participants A randomly selected sample of 1009 adult male prisoners in 13 prisons in England and Wales during 1994/95; structured confidential interviews conducted by independent research staff. Enquiry about prior use of heroin, cocaine or amphetamine focused on three time-periods (ever, last year and last month pre-prison) and the use of these drugs during the first month of imprisonment. Findings A total of 557 (55%) of the 1009 prisoners had used previously one of the three drugs selected for study: 58% had used heroin, 69% cocaine and 75% amphetamine. More than half (59%; 327/557) had used these drugs in the month before the current imprisonment. Drug use in prisons was most likely to occur among those who had used in the month prior to imprisonment. The persistence of heroin use in prison occurred more frequently (70%) than use of cocaine (20%) or amphetamine (15%). Of those using heroin pre-imprisonment, 67% considered they were dependent, compared to 15% and 22%, respectively, for cocaine and amphetamine users. Conclusions Changes in the drug-taking behaviour of drug users after imprisonment vary according to the type of drug being taken. Prisoners were much more likely to continue to use heroin than either cocaine or amphetamines while in prison. Heroin was most likely to be used by those who had been using heroin during the immediate pre-imprisonment period, and particularly by the two-thirds of heroin users who considered themselves dependent. In view of the high prevalence of prior use of these drugs by individuals currently imprisoned, continuing attention is required to study of their behaviour and of the impact of interventions that may be introduced during or following their incarceration. [ABSTRACT FROM AUTHOR]

Some economic costs and consequences of drug misuse and treatment were investigated among clients recruited to the National Treatment Outcome Research Study (NTORS). This was a longitudinal prospective cohort design comprising 549 clients recruited from 54 residential and community treatment programs: data were collected from interviews conducted at treatment intake, at 1 year and at 2-year follow-ups. Treatment costs included index and other drug treatments. Costs were estimated for use of health and social care services, criminal activity and the use of criminal justice resources. Costs were based upon self-reported data collected by structured face-to-face interviews combined with unit cost estimates taken from a variety of sources. Addiction treatment was costed at £2.9 million in the 2 years prior to index treatment, and a further £4.4 million in the subsequent 2 years. Economic benefits were largely accounted for by reduced crime and victim costs of crime. Crime costs fell by £16.1 million during the first year, and by £11.3 million during the second year. Health-care costs were relatively small but approximately doubled during the course of the study. The ratio of consequences to net treatment investment varied from 18:1 to 9.5:1, depending on assumptions. This is likely to be a conservative estimate of the benefit­cost ratio because many potential benefits were not estimated. The data showed clear economic benefits to treating drug misusers in England. [ABSTRACT FROM AUTHOR]

Few studies have investigated methadone treatment of opiate dependent patients in primary health care settings. Using a prospective cohort design, the study investigated outcomes at 1 and 2 years for 240 patients treated by general practitioners (n = 79) or drug clinics (n = 161) at sites across England. Mean daily methadone dose for both groups was 50 mg. Reductions in illicit drug use, injecting, sharing injecting equipment, psychological and physical health problems, and crime, were found in both groups at follow-up. Patients treated in general practitioner (GP) settings reported less frequent benzodiazepine and stimulant use, and fewer psychological health problems at follow-up. Alcohol use outcomes were poor for both groups. Differences in treatment practices were found for GPs and clinics. Results show substantial reductions in a range of problems behaviours, among unselected samples of opiate dependent patients treated in GP and in clinic settings, which are sustained to 1-year and 2-year follow-up. [Copyright &y& Elsevier]

Focuses on the importance of identifying alcohol problems among methadone maintenance patients. Use of multiple strategies for assessing alcohol consumption, alcohol dependence and liver function tests; Provision of useful and satisfactory indicator of drinking behavior through self-reported alcohol consumption.

Aims: To investigate factors associated with first entry to treatment and with treatment re-entry among cocaine users. Design: Cross-sectional study. Setting, participants: Cocaine users (n = 313) recruited from community and treatment settings in Brazil. Measurements: Structured questionnaire including selected items from the addiction severity index (ASI), general health questionnaire, version 28 (GHQ-28), CAGE and the severity of dependence scale (SDS). Findings: Higher dose use, being a problematic drinker and increased awareness of their problem were associated with increased odds of making first contact with an agency. Greater severity of dependence, being involved in acquisitive crime and social support increased the chance of treatment re-entry. Being involved in acquisitive crimes and concerns about confidentiality were associated with decreased odds of first treatment contact. Being a problematic drinker was associated with decreased odds of re-entry treatment. Conclusions: These findings suggest that the distinction between first treatment contact and subsequent entry to treatment is useful, clinically relevant and deserving of further investigation. [ABSTRACT FROM AUTHOR]

This paper describes treatment practices in 54 drug treatment programmes taking part in the National Treatment Outcome Research Study (NTORS). Programmes were representative of the 4 main treatment modalities in the UK: in-patient, residential rehabilitation, methadone maintenance and methadone reduction. Distinguishing features of these forms of treatment were identified. Substantial variations in treatment practices were also observed within each modality, particularly for detoxification and prescribing arrangements, counselling and non-drug treatment services, and planned duration of treatment. Many programmes reported extensive waiting lists. These findings are discussed in the context of the growing international evidence of the association between patient outcome and the manner in which programme services are delivered.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background Criminal activity among drug-misusing populations can result in considerable costs. This paper examines the relationship between acquisitive criminal behaviour and drug use among a cohort of 1075 clients recruited to the National Treatment Outcome Research Study (NTORS). Method Clients were recruited from 54 drug misuse treatment programmes in England. A structured interview was administered by clinical staff. The majority of clients were opiate-dependent poly-drug users. Results Over 27 000 acquisitive criminal offences were reported by the cohort in the three months prior to starting treatment, of which shoplifting was the most common offence. There was marked variation in the amount of acquisitive crime reported; just 10% of the sample were responsible for three-quarters of the crimes committed. Two other groups were identified: low-rate offenders, and those who did not commit an acquisitive crime. Multivariate analyses revealed that frequency of illicit drug use was associated with increased levels of criminal behaviour. Compared with the no-crime group, the high-rate offenders were 11 times more likely to be regular users of heroin, and three times more likely to have used cocaine regularly. Discussion; These findings suggest that the most dependent and problematic drug misusers present treatment services with the greatest challenge in terms of reducing levels of criminality. [ABSTRACT FROM AUTHOR]

The study investigated cannabis use among 200 opiate misusers attending out-patient treatment services at two sites. Three groups were classified according to the frequency of their cannabis use in the previous month; 40.5% were non-users, 40% daily users and the remaining 19.5% were classified as occasional users (they had used on between 1 and 29 days in the previous month). Non-users of cannabis had used heroin in the previous month on more occasions than either daily or occasional users (p< 0.001). Non-cannabis users also reported the highest average frequencies of use of alcohol (p< 0.01) and crack cocaine (p< 0.05). In contrast, daily users of cannabis reported more symptoms of anxiety (p< 0.01) and depression (p< 0.01) than either of the other groups. Finally, daily cannabis users were more likely to report dietary problems than either occasional users or non-users of cannabis. While cannabis use is highly prevalent among opiate misusers in treatment, its relationship to treatment outcome is complex and requires greater research scrutiny. \[Best D, Gossop M, Greenwood J, Marsden J, Lehmann P, Strang J. Cannabis use in relation to illicit drug use and health problems among opiate misusers in treatment. Drug Alcohol Rev 1999;18:31-38]. [ABSTRACT FROM AUTHOR]

Investigates opiate addicts after treatment in Great Britain. Administration of follow-up after discharge; Statistics of patients re-addicted; Collection of data using semistructured interviews.

Aim. To develop a brief, multi-dimensional instrument for assessing treatment outcome for people with drug and/or alcohol problems. The Maudsley Addiction Profile (MAP) is the first instrument to be developed in the United Kingdom for this purpose. Design. Field testing with quota-recruitment of problem drug users and problem alcohol users in treatment with researcher and clinician-administered test-retest interviews. Setting. Two community and two inpatient services at the Bethlem Royal and Maudsley Hospital, London. Participants. Subjects (160 drug users and 80 alcohol users) interviewed by eight interviewers (four researchers and four clinicians), each of whom interviewed 30 subjects on two occasions. Measures. Sixty items across substance use, health risk, physical/psychological health and personal/social functioning domains. Findings. Average completion time of the MAP was 12 minutes. The questionnaire was acceptable to a majority of subjects and performed well with both researcher and clinician interviewers. Internal reliability and feasible concurrent validity assessments of the scales and items were highly satisfactory. Test-retest reliability was good, average intraclass correlation coefficients across eight substances were 0.94 and 0.81 across health risk, health problems, relationship conflict, employment and crime measures. Conclusions. The MAP can serve as a core research instrument with additional outcome measures added as required. The collection of a set of reliable quantitative measures of problems among drug and alcohol users by research or treatment personnel for outcome evaluation purposes need not be time-consuming. [ABSTRACT FROM AUTHOR]

Opioid substitution with oral methadone is the most widely implemented treatment for heroin dependence. In Britain, a complex array of specialist and generic health care services have evolved to deliver this treatment modality. Several minority aspects of British substitution practices receive enduring international interest, including the use of heroin itself as a substitute and the prescribing of methadone in an injectable form. This paper focuses on six linked dimensions that characterize substitution services: (1) treatment providers and settings, (2) prescribing regimes and treatment goals, (3) substitute drugs, (4) dose administration, (5) dose levels, and (6,) substitute formulations. Against a background of increasing central and local accountability for the quality and efficiency of specialist providers and critical attention toward their effectiveness, the strengths and weaknesses of the British approach are considered and key issues and future directions are discussed. [ABSTRACT FROM AUTHOR]

Background: General psychiatrists have recently been encouraged to provide treatment to heroin addicts, including in-patient detoxification. No comparison has previously been made of specialist versus general psychiatric in-patient care.Method: During a randomised study of cue exposure, 186 opiate addicts were also randomised to either specialist in-patient (DDU; n = 115) or general psychiatric (GEN; n = 71) wards in the same hospital.Results: From pre-treatment (post-randomisation) onwards, patient outcomes differed across the two in-patient settings. Of the original randomised sample, significantly more DDU than GEN subjects accepted their randomisation (100 v. 77%), were subsequently admitted (60 v. 42%), and completed in-patient detoxification (45 v. 18%). Of patients admitted, more DDU than GEN patients completed detoxification (75 v. 43%). During seven-month follow-up, of those 43 patients who reached the end of treatment, significantly more ex-DDU than ex-GEN subjects were opiate-free.Conclusions: From pre-treatment onwards, significant differences in process and outcome were found after allocation to treatment on either DDU or GEN. Further randomised studies are required to replicate and explain these findings. [ABSTRACT FROM AUTHOR]

A controlled trial studied whether cue exposure prevented relapse in opiate addiction. Subjects were randomly allocated to one of two inpatient treatment settings: a drug dependence unit with a special 10 week program and 4 weeks in a behavioural/general treatment unit without such a program. In each setting, following drug-withdrawal, subjects had either cue exposure for at least six sessions over 3 weeks, or a control condition. Subjects were followed up twice, at about 6 weeks and 6 months post-treatment. 186 subjects were randomly allocated; 69 were assessed post-detoxification, and of these 43 completed cue exposure or control treatments. Cue exposure and control subjects did not differ in cue reactivity. This was evaluated post-treatment for cue exposure subjects and at a comparable time point for controls. All groups showed a significant decrement in cue-elicited craving, withdrawal responses and negative mood. Cue exposure and control subjects did not differ at either of the two follow up interviews. [ABSTRACT FROM AUTHOR]

This study compares the withdrawal responses of methadone and heroin addicts during a ten-day in-patient detoxification programme with methadone. Contrary to suggestions in the literature, the methadone group reported more severe withdrawal symptoms during both the acute withdrawal phase and the recovery phase. There were no differences between the two groups in onset or duration of symptoms. Whereas there may be reasons to favour methadone as a maintenance drug, its use may lead to difficulties during withdrawal. [ABSTRACT FROM AUTHOR]

The article discusses developments in the government's response to drug abuse problems in Great Britain. The author notes the Maudsley Relapse Project is a study about the return to opiate use of a group of addicts who have been successfully withdrawn from opiates. He adds one particular interest of the project is a previously unreported tendency for substantial numbers of subjects to move towards abstinence during the first six months after leaving treatment. He stresses the treatment program maximizes the chances of success and treatment needs to be extended after discharge from hospital.

The author reflects on the treatment outcomes of drug addicts in the U.S. He discusses different studies on the treatments for drug addicts including the Treatment Outcome Prospective Study (TOPS) which looked into the results of 11,000 patients coming from 41 addiction treatment programs in 10 U.S. cities and the Drug Abuse Treatment Outcome Study (DATOS).

Presents a study on the loss of tolerance and overdose mortality after inpatient opiate detoxification. Discussion about opiate overdose in many countries; Findings that treatment reduces mortality; Description of the participants, methods, and results of the study.

Examines the effect of benzodiazepine use among long-term polydrug-using, opiate addicts in London, England. Impact of the decrease in the availability of temazepam gel-filled capsules; Emphasis on the effect on both the illicit market for diverted prescription drugs and drug-using patterns.

Abstract: Objectives: This study investigates opioid maintenance treatment (OMT) patients found to have corrected QT (QTc) interval above 500ms, with particular focus on past medical history, genetic testing and cardiac investigations. Methods: Detailed medical and cardiac history was obtained, with particular focus upon risk factors. Cardiac investigations, including genetic testing for the five most common long QT syndrome (LQTS) mutations, exercise electrocardiography (ECG) and 24-h ECG recordings, were performed. Results: Of 200 OMT patients assessed with ECG, seven methadone maintained patients identified with QTc interval above 500ms participated in this study. Two were identified as heterozygous LQTS mutation carriers. Both had experienced cardiac symptoms prior to and during OMT. No other risk factors for QTc prolongation were detected among the seven patients. Six of the seven patients underwent further cardiac investigations. QTc intervals fluctuated widely over 24h and during exercise for all patients. Only one of the LQTS mutation carriers switched to buprenorphine and started on a beta-blocker. Despite strong medical advice and information, none of the other patients wanted to switch to buprenorphine or take other cardiac protective measures. Conclusion: Findings indicate the importance of recording a thorough past medical history, focusing specifically on previous cardiac symptoms, and on other known risk factors for QTc prolongation, prior to initiating patients on methadone. [ABSTRACT FROM AUTHOR]

Abstract: Background: This study investigates the prevalence and correlates of hepatitis C virus (HCV) infections among heroin dependent individuals who received methadone maintenance therapy in Taiwan. Also, we investigate users'' awareness of HCV. Methods: Participants were 773 heroin users entering the methadone maintenance treatment (MMT) program at Tsaotun Psychiatric Center in Taiwan. The presence of HCV antibodies was detected. Multivariate logistic regression was used to identify the relationship between HCV infection and correlates. Results: The prevalence of HCV infection was 90.8%. All participants who were HIV-positive were also infected with HCV. Multivariate logistic regression analysis showed that the route of heroin administration (injection), HIV-infection, and criminal records were significantly related to HCV infection. Few (34.8%) HCV positive heroin users were aware of their infection. Conclusion: An extremely high prevalence of HCV infection but low awareness of their infection status was found among MMT patients in Taiwan. These findings highlight the importance of education regarding risky behaviors and the necessity for HCV treatment for this population in Taiwan. [Copyright &y& Elsevier]

Abstract: Background: Naltrexone''s usefulness in the treatment of opioid dependence stems from its ability to block the action of heroin and other opioids. However, many patients are ambivalent towards naltrexone and often drop out of treatment with orally administered naltrexone. Sustained release naltrexone seems promising in reducing opioid use, but the extent to which patients remain in treatment beyond the first dosage of naltrexone is not clear. Methods: Patients (n =61) receving treatment with sustained release naltrexone implants were offered a second naltrexone implant after 6 months. Patients who remained in treatment were compared to those who did not, on drug use, mental health, and social problems before and during naltrexone implant treatment. Information was obtained on other treatments sought by patients who discontinued naltrexone. Blood samples were used to verify naltrexone release, and hair samples to confirm opioid intake. Results: Of the patients who received the first naltrexone implant, 51% (n =31) remained in naltrexone implant treatment. Among those who discontinued treatment, 21% expressed a wish to reimplant but failed to attend for reimplantation and 28% declined reimplantation: 6 non-retained patients initiated maintenance or residential treatment. Remaining in naltrexone treatment was related to pre-study length of employment, illicit drug use, and concern for family problems. Higher levels of substance misuse and criminal activity during naltrexone treatment were negatively related to subsequent retention. Conclusion: Rates of retention among opioid-dependent patients receiving naltrexone implant treatment are encouraging and support this as a feasible long-term treatment option. [Copyright &y& Elsevier]