Specific Aim 1. To test whether aripiprazole preserves LC, PFC and cognitive control function to a greater degree than risperidone in schizophrenia outpatients. Hypothesis 1. ARI group will exhibit greater task-related PFC activity and LC-PFC connectivity than RIS group, after 8 weeks of antipsychotic treatment: (post-antipsychotic Placebo) vs. (pre-antipsychotic Baseline).