Introduction

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Many harmful consequences of heroin use stem from the illegal status of street drugs.^1-3 Drug substitution programmes may alleviate these consequences,⁴ but not all addicts benefit: many continue using street drugs, others drop out, others never enrol. Addicts may fail in oral substitution programmes because they need the "high" caused by heroin injection or the ritual of preparing and injecting the drug. Programmes which provide intravenous heroin may reach such addicts.^5-12

In Switzerland several programmes involving provision of intravenous opiates were started in 1992-5. ^{13 14} Most were evaluated in a before and after design. Only the Geneva heroin maintenance programme was conceived as a randomised trial: eligible addicts were randomised either to immediate admission or to a 6 month waiting list during which time they could receive any other available drug treatment. The research question was whether the experimental programme would improve participants' illegal drug use, health, and social functioning.

	Methods

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Study design and sample
This randomised trial compared outcomes at 6 months in patients allocated to immediate versus delayed admission to the heroin maintenance programme. The planned sample size was two groups of 40 patients. Programme and study procedures were approved by ethics committees in Geneva and Berne.

Experimental programme
The programme clinic was established in September 1995 by the division of substance abuse, Geneva University Hospitals, in central Geneva. Staff included a psychiatrist, an internist, a social worker, five nurses, and a secretary.

Control treatment
Subjects in the control group were encouraged to select any drug treatment programme available in Geneva, were enrolled immediately whenever possible, and were given priority for admission to heroin maintenance after 6 months.

Outcome variables
Outcome variables were consumption of street heroin and other drugs, frequency of overdoses, risk behaviours for HIV infection, numbers of days ill in past month, use of health services, health status, work status, living arrangements, quality of social relationships, monthly living and drug related expenditures, sources of income, and criminal behaviour. The questionnaire (unpublished, based on addiction severity index) was developed by the federal evaluation team, to which we added items to explore specifically the past 6 months, including risk behaviours for HIV infection, and the SF-36 health survey.¹⁵

Analysis
The trial was analysed on an intention to treat basis. For continuous outcome variables we assessed changes over time by the Wilcoxon matched pairs test and differences between groups in change scores by the Mann-Whitney U test.¹⁶ For dichotomous variables we used the McNemar's test for before and after comparisons¹⁶ and tested the homogeneity of McNemar's odds ratio to compare groups.¹⁷ When all changes were in the same direction we compared proportions of individual subjects who changed status. Only exact tests and confidence intervals were used.

	Results

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Enrolment and follow up
Only 73 heroin users (52 men and 21 women, mean age 32 years) applied between September 1995 and March 1996, and 57 were eligible. Among those who were not eligible, 12 did not inject heroin regularly, three were not Geneva residents, three refused to comply with evaluation, and one refused to give up driving. Six eligible people delayed their decision and never provided informed consent. Of 51 patients who agreed to participate, 27 were randomised to immediate and 24 to delayed admission. All experimental group patients and 22 in the control group were reassessed 196 days on average after enrolment (range 168-248); one person from the control group filled only the SF-36 questionnaire. The two remaining patients in the control group were alive at follow up but refused to cooperate.

Baseline description
Participants (table 1) were typically young men who had been injecting heroin for an average of 12 years, had attempted eight drug treatments (range 2 to 21), and had experienced four drug overdoses (range 0 to 30). They had a high prevalence of mental disorders and health status scores 1-2 SD below population norms.¹⁵

Treatments received
One patient allocated to the experimental group never showed up, and another requested transfer to methadone maintenance after one day on heroin. The 25 others received intravenous heroin on average on 168 out of the first 183 days (oral opiates only were given on the remaining days); 20 patients received heroin on more than 80% of treatment days. There were no medical problems with drug injections. The mean daily dose of intravenous heroin was 509 mg (quartiles: 400, 480, 630 mg/day) in one to three injections. Median dose remained stable during the trial (month 1 to 6: 460, 500, 470, 490, 500, and 480 mg/day). Several patients said that they experienced symptoms of craving before injections but did not mind as they knew that the next dose of heroin would be delivered on time.

Use of non-prescribed drugs
At follow up only one (4%) subject in the experimental groupthe person who was never treated but still completed the follow up questionnairebut 10 (48%) in the control group still used street heroin daily (difference 44%; exact 95% confidence interval 16% to 71%; table 2). All experimental patients stopped daily use of street bezodiazepines, and their frequency of overdoses decreased significantly.

Health status
No changes were seen for physical problems or admission to hospital in both groups (table 3). Among patients in the experimental group treatments for mental problems increased and days with mental health problems decreased. Self reported severe depression declined in both groups, but severe anxiety decreased only in the experimental group. Changes in difficulty in controlling violent behaviour and in the number of suicide attempts favoured the experimental group.

Social functioning
Housing situation improved in both groups (table 5). Both groups remained stable in their marital situation and occupational status and both developed more social ties outside the drug scene. Both reported slightly better relationships with their family and social circle (not shown).

Enrolment of controls at follow up
Unexpectedly, only nine (38%) of 24 controls enrolled in the heroin maintenance programme at follow up. Of those who declined, most were successfully treated in methadone maintenance programmes. Main reasons for not wanting to start heroin maintenance were a satisfactory personal situation and the desire to stop injecting drugs.

	Discussion

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This study suggests that a heroin maintenance programme may be a feasible and effective treatment option for severely addicted opiate users. Acceptability was good, as 25 of 27 patients completed 6 months in the programme on stable doses of intravenous heroin. The existence of the programme in an urban neighbourhood caused no disturbance. Thus concerns about feasibility¹⁸ need not hamper further evaluation of heroin maintenance programmes.

The experimental programme was better than other available treatments in several respects. Patients on heroin maintenance no longer used street heroin or street benzodiazepines daily, their mental health and social functioning improved, and they committed fewer suicide attempts, derived less income from illegal activities (particularly from dealing drugs), spent less money on drugs, and committed fewer offences, particularly drug and property related offences. These results are not only significant but also important for the participants' health and social functioning.

Our results are more favourable than those of the only previous trial of heroin maintenance.⁷ The two studies, however, differ considerably. Hartnoll's patients were less severely addicted, received fewer supportive services, could take heroin home, and received only 60 mg of heroin daily. Evaluation methods also differed: the British researchers relied on participant observation while we used quantitative tools.

In other outcomes, experimental patients improved over time, but the difference with patients in the control group was not significant. Examples include fewer drug overdoses, better housing, better overall health status, less severe anxiety, and better precautions against HIV. A larger trial might determine whether heroin maintenance is superior to conventional treatments in these respects. Improvements experienced by controls suggest that even addicts who failed repeatedly in the past may benefit from another trial of conventional drug treatment.

Finally, the experimental programme conferred no advantage in terms of work, legal income, commercial sex, and use of street drugs other than heroin and benzodiazepines.

Limitations of study
Our study has several limitations. Firstly, this was a small trial, similar to initial evaluations of methadone maintenance,^19-21 which threatens the reliability of our findings. Secondly, all outcome measures were self reported, which raises the issue of information bias. Thirdly, because this study assessed global programme effects it cannot differentiate between specific effects of heroin administration and those of other medical and social services, such as mental health care and benzodiazepine substitution. Our results do not support distribution of heroin without such services and certainly not legalisation of heroin.³ We cannot exclude that the benefits of our heroin maintenance programme were entirely attributable to these additional services. Testing the specific contribution of heroin injections would require a trial in which all services but the prescribed opiate would be identical. Nevertheless, psychosocial services alone would probably achieve little as such programmes do not retain patients in treatment.²²