Patients diagnosed with schizophrenia or schizoaffective disorders will be enrolled in the 6-week trial. Eligible patients will receive 9mg paliperidone ER first. Then, the dosage of paliperidone could be adjusted two weeks later according to clinical judgement. They will be followed and receive assessment of pharmacokinetics, metabolic parameters ( lipid profiles, glucose, insulin, adiponectin, leptin, and prolactin, etc.), and the treatment response.
