This study will compare the safety and effectiveness two medications, citalopram (Celexa®) and risperidone (Risperdal®).

Dementia-related behavioral disturbances have been associated with excess disability, increased caregiver burden, and premature institutionalization. Pharmacotherapy is often necessary to treat these disturbances. This study will use citalopram and risperidone to treat people with dementia-related behavior problems.

Participants in this study will begin a psychotropic medication washout period for up to 3 days at study start. Participants will then be randomly assigned to receive either citalopram or risperidone for up to 12 weeks. Limited doses of the sedative lorazepam may be administered as needed throughout the study. During the first 2 weeks of the study, participants will be admitted to a hospital to have their dementia-related behavioral disturbances stabilized. Following hospital discharge, participants will move to a long-term care facility or a residential home and will continue medication treatment for up to 10 weeks. Side effects and improvements in behavioral status will be assessed every week until Week 6 and every 2 weeks thereafter. Experimental laboratory measures will be collected at study start, Week 1, Week 2, and every 2 weeks thereafter until Week 12. Upon study completion, patients may continue to receive citalopram or risperidone under the supervision of their current physicians. Three months after study completion, participants may be contacted for a follow-up report of their psychiatric and medical status.

Inclusion Criteria:

• Diagnosis of Alzheimer's type dementia and/or meet criteria for probable or possible Alzheimer's disease
• Inpatient admittance to Western Psychiatric Institute and Clinic
• Written informed consent from participant's legally authorized representative with the participant's assent
• Psychosis or behavioral problems severe enough to be a danger to the participant's health, well-being, or safety
• Score of 3 to 6 (moderate to severe) on at least one of the Neurobehavioral Rating Scale (NBRS) agitation or psychosis items
• Ability to participate in study evaluation and ingest oral medication

Exclusion Criteria:

• Diagnosis of an unstable medical illness within the last 12 months
• Kidney or liver dysfunction
• Diagnosis of delirium, substance-induced persisting dementia, or vascular dementia
• Score of 12 or higher on the Cornell Scale for Depression in Dementia, and a score greater than 3 on the depression item of the NBRS
• Diagnosis of Parkinson's disease or any neurological illness which may affect cognitive function
• History of schizophrenia, schizoaffective disorder, delusional disorder, psychotic disorders not otherwise specified, or bipolar affective disorder
• Alcohol or substance abuse or dependence
• Receiving monoamine oxidase inhibitors within 15 days of study
• Display behaviors which could endanger the participant's life or the lives of others
• Received fluoxetine within 4 weeks of screening