This study will compare four atypical antipsychotic medications in terms of the risk of specific side effects each of them presents in middle-aged and elderly individuals.

Atypical antipsychotic medications introduced within the last decade have been used increasingly for the treatment of several types of psychotic disorders and severe behavioral disturbances in older individuals. This trend is primarily due to a decrease in side effects caused by the new medications, as compared to conventional neuroleptic medications. There is a lower risk for developing tardive dyskinesia and extrapyramidal symptoms, both of which are movement abnormalities, with new antipsychotic medications. However, there has been a growing concern that the newer medications can cause a different set of potentially serious adverse side effects. Specifically, they may cause long-term metabolic, cardiovascular, and cerebrovascular effects, which may result in weight gain, diabetes, or stroke. This study will compare four atypical antipsychotic medications in terms of the risk of metabolic, cardiovascular, and cerebrovascular side effects that each presents in middle-aged and elderly individuals.

Participants in this open-label study will be randomly assigned to receive one of four atypical antipsychotic medications: aripiprazole; olanzapine; quetiapine; or risperidone. Although assignment is random, a technique that may reflect the participant's own interests or the researcher's knowledge of relevant participant characteristics will be used to assign the participant to a medication. Dosing will be determined by each participant's psychiatrist. Participants will be followed for up to 5 years to assess the side effects of the study medications, with study visits at baseline, Week 6, and every 3 months thereafter.

Inclusion Criteria:

• DSM-IV diagnosis of a disease or disorder that requires treatment with an atypical antipsychotic medication

Exclusion Criteria:

• N/A