Background: The study is to access and compare the long term metabolic adverse effects of olanzapine monotherapy and combined therapy with other antipsychotic in schizophrenia patient on maintenance therapy, to identify the metabolic derangements in patients under monotherapy, combined therapy and other antipsychotic agents. The prospective observational study was conducted in Department of Psychiatric, Rajah Muthiah Medical College Hospital (RMMCH) over 100 patients. The patients/patient care givers were interviewed individually and the entire session was carried at optium privacy to create a favorable environment of acquiring data and providing education. The study shows that combined therapy was more preferred than monotherapy and typical antipsychotics in schizophrenia patients. In this study, WHO Quality of Life BREF, a general questionnaire was selected for evaluating outcome of treatment by measuring the quality of life mainly in four domains, these domains are physical health, psychological, social relationship and environmental domains. In this research the WHO quality of life will be metabolically effected more in monotherapy. This study accomplishes baseline data for future reference.