Effect of psychiatric severity on the outcome of methadone maintenance treatment.

While psychiatric comorbidity has been shown to produce a negative impact on the outcome of opioid use disorders, longitudinal studies carried out in the context of methadone maintenance treatment programs (MMTP) to evaluate outcomes strictly linked to methadone efficacy have not demonstrated a similar negative influence. To verify whether results obtained considering psychopathology in terms of formal psychiatric diagnoses were replicated when assessing psychopathology in terms of global psychiatric severity, a retrospective cohort study was designed. 259 patients commencing methadone maintenance treatment were divided into two groups on the basis of SCL-90 severity score and compared for retention in treatment, toxicological urine test results and psychological/psychiatric status throughout a one year period of observation. The results of the study suggest that patients in MMTP with high psychiatric severity are not characterized by a lower retention in treatment or higher substance use than those with low psychiatric severity. Moreover, during treatment high severe psychiatric patient status appears to improve significantly for all psychological/psychiatric dimensions explored by SCL-90. These results are consistent with those obtained in previous studies on the efficacy of MMTP, comprehensive of psychiatric care, irrespective of the severity of psychopathology exhibited by patients at the beginning of treatment.