Objectives: The aims of the study were: 1. To evaluate the efficacy of olanzapine in patients on methadone maintenance treatment; 2. To explore the time-course variation of cravings and weight at baseline and every 2 months for the first 6 months and then every 6 months until the end of the study (30 months). 3. To compare the severity of the symptoms between patients on methadone and patients on buprenorphine.
Methods: The patients were enrolled from the Outpatient Addiction Unit in Bologna, Italy. All patients gave written informed consent. We randomized 32 patients to treatment with methadone and 13 to treatment with buprenorphine. Based on inclusion and exclusion criteria, 36 patients were included in the study and they were divided into three treatment groups. At the baseline and follow-up sessions the following rating scales were administered: The Minnesota Multiphasic Personality Inventory-2 (MMPI-2), the SCID-II (to identify and determine DSM-IV Axis II disorders i.e. personality disorders), Bech-Rafaelsen Mania and Melancholia Scales (BRMAS, BRMES; Bech et al. 1988, to cover severity of manic and depressive symptoms, respectively), and a VAS (Visual Analogic Scale, to quantify craving for drugs). Also the body weight of the participants was registered and followed.
Results: After six months, no significant difference was found among the three subgroups, even though the olanzapine+methadone group achieved better and quicker results and sustained them for longer periods. There was no significant difference at baseline and at the end of the study in all patients. Total and partial BRMES and BRMAS scores did not significantly change during the follow-up period (6th-30th month), eventhough the curve displayed a downward trend. The VAS total scores were significantly lower both at the 6th and 30th month (p< 0.0001) when compared to the baseline condition. None of the three treatment subgroups showed a significant weight gain, both after 6 months (at this follow up we observed better results in the treatment of mania and melancholia) and at the end of the study (eventhough there was a small peak of weight gain). At the 30th month we considered the BRMAS and BRMES scores corresponding to the maintenance phase. Three patients dropped out from the study just before the 30th month session because they stopped olanzapine due to weight gain (5kg for one patient, and 3 kg for two patients).
Conclusions: We observed good adherence to antipsychotic treatment in this sample and we did not detect metabolic complications. Buprenorphine was prescribed for younger patients and patients with lower severity of symptoms. At the 30th month, all urine drug tests were negative. It is likely that the constant caregiving and clinical monitoring improved the patients' motivation and adherence to the treatment. This point is important because the number of patients needing addiction treatment has been increasing, while time and available resources are limited. According to the results of this study, the use of methadone and olanzapine together in the treatment in psychotic substance abusers improved treatment adherence, even in the presence of subthreshold psychiatric symptoms.