Psychosis of Alzheimer disease: validity of the construct and response to risperidone.

Objective: The authors evaluated the efficacy of risperidone in reducing psychotic and aggressive symptoms in a subgroup of patients who fulfilled operationalized criteria for psychosis of dementia.

Methods: Authors conducted a subgroup analysis of patients in the risperidone database arising from a previous double-blind, randomized, placebo-controlled study. In the primary study, patients age 55 or older, with a DSM-IV diagnosis of Alzheimer disease and/or vascular dementia were randomized to placebo or 0.5 mg, 1.0 mg, or 2.0 mg/day of risperidone. For this analysis, patients were selected who fulfilled operationalized criteria for psychosis of dementia. These criteria were then validated. The primary outcome measures were the newly developed Psychosis and Aggression Severity Indices, derived from Parts 1 and 2 of the BEHAVE-AD rating scale.

Results: At Week 12 and endpoint, patients with psychosis of dementia receiving 1 mg or 2 mg/day of risperidone showed significantly more improvement on the Psychosis Severity and Aggressiveness Severity Indices than those receiving placebo.

Conclusions: The construct of psychosis of dementia was validated, and the severity of both psychosis and aggressiveness was reduced with risperidone treatment in a robust and dose-related way, with a continuing response over the 12-week trial period.