Delirium and mental health history as predictors of aggression in individuals with dementia in inpatient settings.

Objectives: Aggressive behaviors by patients with dementia present risk to health care workers and patients. An information processing model, developed to study aggressive behaviors among children, was applied to study aggression among older hospital patients with dementia. Hypotheses were that delirium and mental health or depression history, would relate to increased risk of aggressive behaviors.

Method: Electronic medical records were sampled for one year (n = 5008) and screened using the EMERSE search engine and hand review for dementia (n = 505) and aggressive behavior in individuals with dementia (n = 121). Records were reviewed for mental health history and presence of delirium.

Results: Regression analyses found interaction effects representing delirium and mental health or depression history associated with greater risk of aggressive behavior. Significant main effects were found for both dementia and mental health or depression history. Of the lowest risk group, 12% of patients exhibited aggression compared to 24%-35% of those with delirium, mental health or depression history, or the combination of these risk factors.

Conclusion: Delirium is the leading correlate of aggressive behaviors in hospitalized patients with dementia, and delirium or history of mental health diagnosis may lead to increased risk of aggressive behaviors in this setting.