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.

The purpose of this study is to use a direct measure of brain volume and matter (by means of MRI) to determine if there is a differential effect between aripiprazole and risperidone on brain morphology in participants with first-episode psychosis. A secondary objective is to see if fasting metabolic indices measured in the blood (i.e. glucose, insulin, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, adiponectin and leptin) are also correlated to changes in brain morphology or symptom severity (as measured by neuropsychiatric assessments).

Inclusion Criteria:

• Male or female, aged 12+ years for healthy participants or participants with bipolar disorder; or aged 15+ years for participants with non-affective psychosis.
• Recent admission to the Vancouver/Richmond Early Psychosis Intervention (EPI) program related to first episode psychosis or first episode bipolar disorder;
• Participants being treated with an antipsychotic medication principally for psychosis or for bipolar disorder.
• Participants taking aripiprazole must be taking a dose of at least 10mg/day for the duration of the study.
• Participants must have received a minimum of 3 months of continuous antipsychotic drug treatment with either aripiprazole or risperidone principally for psychosis or bipolar disorder;
• Participants may be in- or outpatients.
• Participants able to give informed consent, or informed consent through legally authorized representative.

Exclusion Criteria:

• Total life time exposure to the antipsychotic drug aripiprazole vs risperidone for less than 3 months at time of consent.
• Previously diagnosed with diabetes mellitus, seizure disorders, mental retardation (IQ < 70), or pregnancy (current or within 3 months postpartum)
• Participants who have been treated/are currently being treated with mood stabilizers (paroxetine, lithium, or valproic acid). Prior or concurrent use of Selective Serotonin Reuptake Inhibitor antidepressants (other than paroxetine) is acceptable..
• Received antipsychotic polypharmacy (treatment with more than one antipsychotic drug)
• Participants who are not able to fluently communicate in English.
• Contraindicated for MRI scan (i.e., has had major surgery in the last 6 months, morbid obesity, claustrophobia, and/or has metal in their bodies from a surgical intervention or working in metalwork, or is unsure if metal is present in their bodies, etc.)

Patients admitted to Vancouver.Richmond EPI program who have been on at least 3 months of continuous antipsychotic drug treatment with either aripiprazole or risperidone for first-episode psychosis or bipolar disorder, and healthy controls.