OBJECTIVES: Olanzapine Long-Acting Injection (OLAI) was developed to provide individuals with schizophrenia, particularly those who struggle with adherence, with an effective and convenient alternative to oral antipsychotics.  The present study compared quality of life and patient-reported outcomes between oral and long-acting injectable formulations of olanzapine in the treatment of schizophrenia.   METHODS: Clinician-rated quality of life and patient-reported outcomes were evaluated in a 24-week double-blind, randomized clinical trial comparing OLAI with oral olanzapine in clinically stabilized individuals with schizophrenia. The measures used included the Heinrichs-Carpenter Quality of Life Scale (QLS), the Short Form Health Survey (SF-36), and the Drug Attitude Inventory (DAI).    RESULTS: Of the 1065 randomized individuals, the majority were male (65.4%) and Caucasian (71.8%), with a mean age of 39 years and a baseline PANSS Total score of 55.9 (SD=15.6).  In general changes in QLS, SF-36, and DAI for individuals on OLAI were similar to those for individuals receiving oral olanzapine with the exception of statistically significant differences on some SF-36 subscales.  However these differences across treatment groups were not considered clinically meaningful.  Despite examination in a symptomatically stable population, significant improvements in quality of life as measured by the QLS total scores were seen in the group taking OLAI for two of the three therapeutic doses (405mg/4wk, p<0.001 and 300mg/2wk, p=0.003) and the group taking oral olanzapine (p<0.001).  There were no significant differences in QLS across treatment groups.  CONCLUSIONS: Subjects remained stable over the course of the study, and many experienced an increase in quality of life regardless of assignment to OLAI or oral olanzapine.  The findings suggest symptomatically stable individuals receiving OLAI will maintain health outcomes comparable with those taking oral olanzapine. OLAI may be useful for individuals who desire the effectiveness of olanzapine without requiring daily dosing.