• The primary endpoint in this study is to be the change from baseline in total PANSS score. The primary evaluation time is to be at the final evaluation (when the evaluation was conducted finally in the subjects, i.e., at 6 weeks in LOCF data). [ Time Frame: From baseline to the final evaluation ] [ Designated as safety issue: Yes ]
  

• 1) Proportion of responders 2) PANSS subscale score (positive symptoms, negative symptoms, general psychopathology, disorganized thoughts, hostility/ excitement, anxiety/ depression) 3) CGI-S [ Time Frame: From baseline to the final evaluation ] [ Designated as safety issue: Yes ]
  

This is a multicenter, double blind (nether the patient nor the physician knows whether drug or placebo is being taken, or at what dosage), randomized (patients are assigned different treatments based on chance), placebo- and active-controlled, parallel-group study. Subjects will be randomized into 1 of 3 treatment groups to receive oral dosages of ER OROS paliperidone 6 mg, olanzapine 10 mg, or placebo once daily for a 6-week period. The study will include a screening period, followed by double-blind treatment for 6 weeks. Following the double-blind treatment phase, eligible subjects (those who have completed the 6-week double-blind phase or who discontinue due to lack of efficacy after a minimum of 14 days) may enter the 48-week open-label extension with ER OROS paliperidone therapy. A post-study visit for collection of additional safety data will be scheduled for 1 week after a subject's final dose of study drug, either following the double-blind phase for those subjects not continuing into the open-label extension, or following the open-label extension. For all subjects exiting the study - whether they are withdrawn early from either phase, or complete the double blind and/or open-label phase - the investigator will make every effort to see that patients receive an adequate continuity of care.

The Patients will receive two capsules of Paliperidone ER 3 mg, placebo or Olanzapine 5 mg once daily after breakfast for 6 weeks.

Inclusion Criteria:

• Patients who have given their own consent in writing to participate in the study. - Patients diagnosed with schizophrenia according to the diagnostic criteria of DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 295.30, 295.10, 295.20, 295.90, 295.60). - Patients who have acute symptoms of schizophrenia. - Both inpatients and outpatients are acceptable

Exclusion Criteria:

• A DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) a mental disease diagnosis other than schizophrenia. - A DSM-IV diagnosis of substance-related disorder (except nicotine dependence and caffeine dependence) within 180 days before the screening test. - Total PANSS (Positive and Negative Syndrome System) score at the screening test <70 or >120. - Patients treated with three or more types of antipsychotic within 28 days before the screening test. - Parkinson's disease (except for those with drug-induced extra pyramidal symptoms) : Patients with a complication of or a past history of cerebrovascular accident. - Patients with a complication of or a past history of diabetes mellitus