Safety and Efficacy of Study Drug Versus Placebo for Negative Symptoms of Schizophrenia

Inclusion: * Adults aged 18-60 * Current diagnosis of schizophrenia * Significant negative symptoms with few positive symptoms (e.g. hallucinations, delusions) and no evidence of major depression. * Female subjects of childbearing potential must test negative for pregnancy at the time of enrollment. * Subjects must be able to provide consent * Must be healthy based on medical exam, laboratory tests and electrocardiogram Exclusion: * Female subjects who are either pregnant or nursing. * Acute or unstable medical conditions * Diseases of the central nervous system * Subjects who are judged clinically to be at serious risk for suicide or violence * Subjects with delusional disorder, psychotic disorder NOS, schizophreniform, schizoaffective disorder, bipolar disorder, attention deficit/hyperactivity disorder, major depressive disorder,alcohol or drug dependence