Study To Assess Differential Sensitivity Of 2 Spatial Working Memory Tests In Schizophrenics Treated With Risperidone

Inclusion Criteria: * Male or female, 18 to 50 years old, antipsychotic-naive, non-agitated patients diagnosed with first-episode schizophrenia or schizophreniform disorder. Exclusion Criteria: * Evidence or history of clinically significant medical or non-medical impairment that, in the opinion of the investigator, would affect the safety of the patient or interfere with the evaluation of the trial results; * Patients who have a history of substance (which included alcohol) dependence within 12 months or abuse within 3 months of enrollment, or tested positive for an illicit drug on the Screening urine toxicology test * Pregnant or nursing females; females of childbearing potential who are unwilling or unable to use an acceptable method of contraception