Switching outpatients with schizophrenia and related disorders on long-acting injectable antipsychotics to olanzapine: an open-label naturalistic pilot study.

Little is known about the feasibility of switching patients with schizophrenia from long-acting injectable antipsychotics to oral olanzapine. We completed an open-label 14-week study to assess such a transition. This study included 25 stable outpatients (DSM-IV diagnosis of schizophrenia, schizophreniform disorder, or schizoaffective disorder) who were receiving long-acting injectable antipsychotics. Following a screening visit, patients began treatment with olanzapine 10 mg/day, which was initiated the day of their scheduled injection. Clinical assessments included the Clinical Global Impression-Improvement Scale (CGI-I) and the Positive and Negative Syndrome Scale (PANSS). Patient self-reports of adverse events were monitored and the Extrapyramidal Symptoms Rating Scale completed at each visit. In those completing the trial (N = 18), results revealed that a switch from injectable antipsychotics to olanzapine was associated with significant improvements on the CGI-I, negative symptoms, PANSS total scores, and parkinsonism. In considering the whole sample (last observation carried forward, N = 25), significant improvements on the CGI-I, parkinsonism, and dyskinesia were observed. Finally, those who failed to complete the trial (N = 7) did not change significantly from visit 1 to endpoint on any of the efficacy or safety measures. These results should be considered preliminary and require replication using appropriate control groups.