PSYCHOTIC SYMPTOMS AND PHYSICALLY AGGRESSIVE-BEHAVIOR IN ALZHEIMERS-DISEASE

OBJECTIVE: To examine the relationship between psychotic symptoms and subsequent physically aggressive behavior in outpatients with Alzheime r's disease. DESIGN: This observational study used a time series desig n to measure the presence and frequency of physically aggressive behav ior over a 52-week period. Multiple regression models were used to eva luate delusions and hallucinations, assessed at baseline, as predictor s of physical aggression, controlling for demographic and clinical var iables. SETTING AND PARTICIPANTS: Of 315 consecutive eligible outpatie nts from the Rush Alzheimer's Disease Center, referred for evaluation for dementia, 270 (86%) participated in the study. All participants me t NINCDS/ADRDA criteria for probable Alzheimer's disease; Mini-Mental State Examination scores ranged from 0 to 27, with a mean of 14.9 (SD = 5.6). MEASUREMENTS: Psychotic symptoms, previous episodes of physica l aggression, and demographic variables were measured at baseline thro ugh a structured interview with an informant living in the same househ old. Physically aggressive behavior was measured sequentially at 1-wee k intervals over a period of 52 consecutive weeks and also through str uctured informant interviews. RESULTS: A total of 75 persons had one o r more episodes of physical aggression during the 52 weeks of observat ion. The presence of delusions significantly predicted the presence an d frequency of physical aggression. Of participants with high rates of physical aggression (>1 episode/month), 80% had delusions. This effec t was robust, even after controlling for the effects of other clinical variables. By contrast, hallucinations did not reliably predict episo des of physical aggression. CONCLUSIONS: These data suggest that delus ions, but not hallucinations, predict physically aggressive behavior i n persons with Alzheimer's disease. In light of the persecutory nature of most delusional ideation in Alzheimer's disease, delusions may be associated with distortions in the perception of threat in common soci al situations.