The purpose of this study is to assess whether SCH 900435 (Org 25935) 16 mg twice daily is more effective than placebo in the treatment of patients with schizophrenia, using olanzapine 15 mg once daily as active control.

Inclusion Criteria:

• Subjects eligible to participate:

  • present a substantial and recent exacerbation of schizophrenia
  • have responded positively to treatment with an antipsychotic other than clozapine in the past
  • are without adequate treatment for their symptoms, or willing and capable to stop concurrent medication, which appears inadequate to treat their condition, prior to participation

Exclusion Criteria:

• Schizoaffective disorder;
• single episode of schizophrenia in partial remission
• concomitant use of antidepressants, mood-stabilizers (including anticonvulsants) or long-acting sedatives
• substance abuse or dependence (excluding nicotine and caffeine)
• uncompensated medical illness (including clinically relevant eye disorder)