<qa>  What will the subjects with schizophrenia have their antipsychotic medication tapered and switched to?The subjects with schizophrenia will have their antipsychotic medication tapered and switched to aripiprazole during a twelve week treatment phase. They will be seen at the end of Week 1, Week 2, Week 4, Week 6, Week 8, Week 10, and Week 12. At the last visit the fMRI scan will be repeated during the same reward task. 