 Significant changes in brain morphology are observed in people with first-episode psychosis. Studies have shown that total brain volume and particular brain structures are decreased in people with psychosis disorders. Recent evidence suggests that some atypical antipsychotic drugs can maintain or increase brain volumes. Thus, we plan to use MRI scans to measure changes in brain morphology in subjects recently diagnosed with bipolar or psychosis disorders who are taking the atypical antipsychotic drugs aripiprazole or risperidone. Secondary objectives include taking blood samples for fasting metabolic indices and neuropsychiatric measures for comparisons between drug treatments. 