Perneger 1998.

Methods	Allocation: randomised controlled trial; Randomization Blindness of patients in respect to treatment: non described. Duration of treatment within the study: 6 months
Participants	Diagnosis: Heroin addicts; N=51 age >20; use >2yrs (12 years on average); more previous attempt of drug treatments (average 8 range 2‐21) and had experienced four drug overdoses (range 0‐30); high prevalence of mental disorders and health status scores 1‐2 SD below population norms.
Interventions	Heroin injected by the patients themselves + oral methadone if the patient travels or want to reduce the attendance of the clinic; mean daily dosages of intravenous heroin was 509 mg/day in one to three injections; in addition to heroin all the patients occasionally received oral opiates and 16 patients received clorazepate substitution therapy (median dose 60 mg/day) psychological support (N=27) Any other conventional drug treatment (N=24) control: waiting list (control patients were encouraged to select any drug treatment program available in Geneva and were enrolled immediately whenever possible). Psychosocial treatment: all patients received psychological counselling, HIV prevention counselling, social and legal support services, and somatic primary care.
Outcomes	Consumption of street heroin; frequency of overdoses; risk behaviour for HIV; number of days ill in the past months; 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, retention in treatment.
Notes	Country: Switzerland 1995‐1996
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"computer generated list of numbers placed in sealed envelopes".
Allocation concealment (selection bias)	Low risk	Patients are allocated by the psychiatrist during the first visit through the sealed envelopes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All experimental group patients and 22 in the control group were reassessed 196 days on average after enrolment (range 168­248); one person from the control group filled only the SF­36 questionnaire. The two remaining patients in the control group were alive at follow up but refused to cooperate.
Selective reporting (reporting bias)	Unclear risk	Protocol not identified probably due to the date of the study.
Blinding (objective outcomes: drop out, use of substances measured by urine analysis)	High risk	no objective measures adopted: all outcome measures were self reported, which raises the issue of information bias.
Blinding (subjective outcomes: use of substances as measured by self report, side effects)	High risk	no actions to reduce the risks reported