The Andalusian trial on heroin-assisted treatment: a 2 year follow-up.
Oviedo-Joekes E., March J.C., Romero M. et al. Drug and Alcohol Review: 2010, 29(1), p. 75–80.

Heroin/cocaine addicts in Granada in Spain who were being prescribed heroin made greater sustained improvements in their illicit heroin use, crime and psychological health and showed signs of more social reintegration than patients who nearly three years before had been randomly allocated to methadone.

Summary Deriving from a study in Granada in Spain, the featured report is based on re-interviews with 54 of 62 patients addicted to heroin/cocaine, on average just over two years after the end of a nine-month period during which they had been randomly allocated to oral methadone maintenance, or this plus injectable heroin consumed under supervision at the clinic twice a day. To enter the trial patients had to be injecting opiates despite having been in methadone treatment at least twice in the past, and to be suffering from at least two of: injecting-related infectious disease; mental health problems; substantial social/family problems or criminal activity.

After the nine months during which they had been randomly allocated to heroin or methadone, patients still being prescribed heroin were allowed to continue, and those prescribed only methadone could be switched to heroin (13 of 31 were) if they wanted to and if they met legal criteria for this option as a 'compassionate treatment'. At the final follow-up this created three groups: patients currently being prescribed heroin after being randomly allocated to it or switched from methadone-only; patients prescribed heroin but who had discontinued this treatment; patients allocated to methadone-only and never subsequently prescribed heroin. The featured report compares long-term outcomes between these categories. An earlier paper also drawn on in this account reported on outcomes during the nine-month randomisation period.