Contrasting the Brain Effects of Risperidone and Invega With Functional Magnetic Resonance Imaging (fMRI) and Positron Emission Tomography (PET) Scanning

Inclusion Criteria: * are currently taking Risperdal and have been on the medication for at least three weeks * are diagnosed with schizophrenia * are able to provide written informed consent * can safely have an MRI Exclusion Criteria: * are treatment resistant or intolerant to Risperdal * have participated in another drug study in the past 28 days * are pregnant or trying to become pregnant or are breastfeeding * are colorblind * have a history of alcohol, cannabis, or cocaine abuse within two weeks prior to the study * have a current or past history of a major medical illness or have abnormal lab values which the study doctor feels is significant * certain medications are also exclusionary including aripiprazole.