Alzheimer's disease has been associated with serious behavioral disturbances including aggressive behaviors and agitation. Aggression in dementia of the Alzheimer's type may be associated with psychotic symptoms, particularly delusional misidentification phenomena. This article describes the case of a man suffering from Alzheimer's disease who threatened to shoot his wife as he believed her to be an impostor. It attempts to explicate the genesis of his aggressiveness in part as a function of his psychiatric phenomenology. It also discusses the case from the standpoint of the current state of knowledge of the biology of delusional misidentification, and examines development of treatment approaches. The article suggests the need for further study of the degree to which delusional misidentification may lead to physical aggression in the context of dementia. Further study could generate improved biologic, behavioral, and environmental treatments, such as trials involving the newer atypical antipsychotics and mood-stabilizing medications, and applications of behavioral, supportive, and environmental interventions to optimize psychosocial outcomes. References