Schizophrenia and bipolar disorder are renowned for chronic and deteriorating course. Although atypical antipsychotics and mood stabilizers are widely used as treatment of choice for these illness based on acute efficacy and safety, long-term efficacy and safety of these agents are still open to debate. Prospective follow-up study in naturalistic condition may be a useful way of elucidating cons and pros of long-term psychopharmacotherapy.In this study, efficacy and various side effects of drugs will be measured, and the possibility of neurophysiological markers will be tested by serial measurements of electroencephalographic changes.

Inclusion Criteria:

• Male or female patients, 18-65 years of age.
• Patients must have a diagnosis of schizophrenia or bipolar disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).
• Patients have not been received antipsychotics or mood stabilizers within the past 4 weeks prior to the study entry.
• Each patient must provide written informed consent after full explanation of study protocol, and authorized legal guardian must understand the nature of the study and must also give assent to study participation.

Exclusion Criteria:

• History of taking antipsychotics or mood stabilizers within past 4 weeks.
• History of DSM-IV substance dependence.
• Mental retardation (IQ < 70)or patients who are not able to understand the informed consent.
• Definite or suspected organic mental disorders.
• Female patients who are not able to maintain contraception during this study
• Laboratory abnormalities with clinical significance
• History of epilepsy or electroconvulsive therapy within the past 3 months.