Cognitive Improvement With Aripiprazole (Abilify) in Patients With Schizophrenia (BMS)

* Long-range goal is to understand how the schizophrenic brain is abnormal, as well as how the function of the brain changes in response to antipsychotic medication, to better understand and effectively treat disorders with these drugs. This information can be used in other disorder as well, as there are many psychiatric disorders that are targeted by the newer atypical antipsychotics. * The objective of this application, which is the next step in pursuit of the long-range goal, is to compare response on a series of cognitive tests (verbal learning, working memory, and attention) and changes in brain activity in a group of patients with schizophrenia or schizoaffective disorder who are taking risperidone, olanzapine, or risperidone Consta injections and who switch to aripiprazole, and in a group of normal control subjects evaluated twice to control for learning effects. * The central hypothesis of this application is that patients with schizophrenia or schizoaffective disorder that are taking aripiprazole will have improvements in cognition consistent with the medication's efficacy. We expect that changes in brain activity (from fMRI and EEG) will be correlated with this improvement, as determined by performance on cognitive tests. Further, changes in regional connectivity of affected brain regions will reflect these specific cognitive changes related to aripiprazole. * The rationale for this proposed study is that, once we have a better understanding of which drugs improve cognition and what brain regions respond differently to aripiprazole and risperidone, olanzapine, or risperidone Consta, we will have a better understanding of the functional differences tied to the differential actions of the drugs. This is important, because we really don't understand how these medications affect cognition.