Safety and Cognitive Function Study of EVP-6124 in Patients With Schizophrenia

Inclusion Criteria: * Subjects who meet clinical criteria for schizophrenia or schizo-affective disorder utilizing the structured clinical interview (SCI) * Must be treated with a second generation anti-psychotic drug other than clozapine at a stable dose for at least 4 weeks and must have been on that drug and clinically stable for at least 8 weeks * Must have no more than "moderate" severity rating for negative symptoms: BPRS item ≤4 * A minimal level of extrapyramidal symptoms (EPS); Simpson-Angus Scale total score ≤6 * A minimal level of depression; Calgary Depression Scale total score ≤10 * Must have a general health status acceptable for participation in a 12-week clinical trial * Fluency (oral and written) in the language in which the standardized tests will be administered * If a smoker, the ability to refrain from smoking for at least 30 minutes prior to any cognitive testing Exclusion Criteria: General * Insufficiently controlled diabetes mellitus in the judgment of the investigator * Malignant tumor within the last 5 years with the exception of squamous and basal cell carcinoma or cervical carcinoma it situ * Pregnancy, nursing, (or if fertile female) not willing to utilize birth control measures during study * Unstable medical condition that is clinically significant in the judgment of the investigator: major organ system dysfunction