"In this trial, patients assigned to receive injectable diacetylmorphine were more likely to stay in treatment and to reduce their use of illegal drugs and other illegal activities than patients assigned to receive oral methadone. These findings are consistent with the results of European studies that suggest greater effectiveness of diacetylmorphine than methadone as maintenance treatment for long-term, treatment-refractory opioid use.10,12,13 Two of these trials showed no differences between groups in the rate of retention in treatment for addiction. However, the fact that control patients were eligible to receive diacetylmorphine at the end of the study period may have introduced a bias in the observed retention rates. In addition, patients currently enrolled in methadone maintenance treatment were eligible for the European trials but not for the present study. Although the definitions of clinical response varied among the trials, all of them considered the same variables (drug use, illegal activities, health, and social adjustment) and showed greater effectiveness of diacetylmorphine than of methadone for maintenance treatment.

"Secondary analyses showed that both groups had significant improvement in many of the variables that were evaluated. The diacetylmorphine group had greater improvements with respect to medical and psychiatric status, economic status, employment situation, and family and social relations. These results are particularly noteworthy in view of the nature of the population and the time frame. The fact that patients who received diacetylmorphine had significant improvement in these areas suggests a positive treatment effect beyond a reduction in illicit-drug use or other illegal activities."

Source

Oviedo-Joekes, E., Brissette, S., Marsh, D. C., Lauzon, P., Guh, D., Anis, A., & Schechter, M. T. (2009). Diacetylmorphine versus methadone for the treatment of opioid addiction. The New England journal of medicine, 361(8), 777–786. https://doi.org/10.1056/NEJMo…