[The impact of substitution treatment by methadone among opiate-dependent subjects evaluated by Addiction Severity Index and by urine tests]. / Impact d'un traitement de substitution par méthadone sur des sujets dépendants aux opiacés évalué par l'Addiction Severity Index et des contrôles urinaires.

Methadone maintenance treatment (MMT) has been evaluated in the United States and in a few other countries. MMT has been developed in France since 1995, and over 5 000 patients receive this treatment. However no French study has yet been published on the efficacy of MMT as assessed by a validated scale. Retention in treatment for one year has been considered as a threshold to define maintenance of treatment benefits after discharge from a methadone program; determination of retention predictors is important. Over a three year period, we evaluated patients at admission and during treatment using the Addiction Severity Index (ASI), and urine drug screening was performed weekly; 95 patients (66 males and 29 females) were evaluated at intake. Their mean age was 30.2 5.5, and they had used opioids for a mean of 10.6 5.7 years. Their ASI severity scores for drugs were over 5, showing a clear need for treatment. Female patients differed from males only in the employment-finances ASI score; 43 patients completed at least one year of treatment, after which their drug and legal composite scores significantly improved. No significant changes in their consumption of cocaine, alcohol, benzodiazepines or cannabis were found, but they smoked fewer cigarettes at 12 months. Demographics, ASI severity scores, and history of suicide attempts did not differentiate one-year completers from dropouts (n=16). However, dropouts had used more buprenorphine and less methadone in the 30 days preceding their admission, and they received a lower dose of methadone during treatment. Our population is comparable to other French MMT populations; they enter treatment after a long history of opioid dependence. The improvement found on the ASI composite scores is also similar to the improvement described in other international studies. Dropouts in our study seem to be more treatment-resistant patients, in the sense that they had used more buprenorphine before intake and were not stabilized with it; and they may have had a more negative attitude towards methadone.