The Comparison of Efficacy and Safety of Continuing Olanzapine to Switching to Quetiapine in Overweight or Obese Patients With Schizophrenia and Schizoaffective Disorder

The primary objective of this study is to assess the treatment difference in time to relapse while on olanzapine 7.5-20 mg/day versus quetiapine 300-800 mg/day in the treatment of obese or overweight patients

with schizophrenia or schizoaffective disorder. Relapse is defined as the occurrence of at least one of the following three conditions:

Hospitalization for psychiatric reasons after Visit 2, or

20% worsening on the Positive and Negative Syndrome Sale (PANSS) Total and an increase in level of care, as compared to Visit 2, or

20% worsening on the PANSS Total compared to Visit 2 and worsening of CGI-S by at least one level compared to Visit 2 and CGI-S level of at least 4 (moderately ill).

To assess within and between group changes in metabolic parameters including fasting glucose, hemoglobin Alc, lipids, and insulin

To assess within and between group changes in weight, waist circumference, BMI, appetite, and prevalence of patients meeting criteria for the metabolic syndrome

To assess within and between group changes in metabolic parameters (fasting glucose and lipids, and hemoglobin A1c) in a sub-group of patients with pre-existing diabetes prior to study entry

To assess the effect of olanzapine versus quetiapine on time to discontinuation for any reason, or lack of efficacy or worsening of psychiatric syndromes

To assess the efficacy of olanzapine versus quetiapine in improving psychopathology of schizophrenia as measured by a mean change from baseline on the PANSS and the Clinical Global Impression-Severity (CGI-S)

Scale as well as by absolute score of CGI-I (Improvement Scale)

To assess the efficacy of olanzapine versus quetiapine in improving depressive symptoms as measured by a mean change from baseline on the montgomery-Asberg Depression Rating Scale (MADRS)

To assess the efficacy of olanzapine versus quetiapine in improving patients' general well being and overall level of functioning as measured by the Short Form 36 Health Survey (SF-36), the Patient Global Impression (PGI)Scale,

and the Global Assessment of Functioning (GAF) Scale

To assess patients' opinions on the treatment with olanzapine versus quetiapine as measured by the Drug Attitude Inventory (DAI-10) Scale

To compare the utilization of medical resources between patients treated with olanzapine or quetiapine

To assess the safety of olanzapine and quetiapine as determined by:

Treatment-emergent adverse events

Vital signs and fasting laboratory analytes

Extrapyramidal symptoms as measured by the Modified Simpson-Angus Scale, the Barnes Akathisia Rating Scale, and the Abnormal Involuntary Movement Scale (AIMS)

A sensitivity analysis will be performed on two randomly chosen subsamples of the overall patient population by analyzing the primary objective respectively