The purpose of this study is to determine whether a low dose and a high dose of the study drug SCA-136 are effective and safe in the treatment of schizophrenia requiring hospitalization.

Inclusion Criteria:

• Clinical diagnosis of schizophrenia
• Ability to remain hospitalized for at least first 4 weeks of study
• Needs hospitalization due to worsening of schizophrenia

Exclusion Criteria:

• Type 1 or 2 diabetes
• Previous use of clozapine
• Serious medical illness other than schizophrenia