Pathophysiology of Behavioral and Psychological Disturbances in Dementia

Although dementia is frequently thought of as an impairment in cogni­tion, a common and often overwhelming dilemma facing many families and clinicians is the presence of behavioral and psychological disturbances during the course of the illness. These can include depressive signs and symptoms, agitated behaviors, and psychotic symptoms. It is estimated that as many as 40% to 90% of individuals diagnosed with dementia will experience behavioral or psychological disturbances during the course of their illness (Teri et al 1992; Zuidema et al 2006). The presence of such symptoms is detrimental to patients and their caregivers and results in increased rates of caregiver burn-out, depression, and earlier institution­alization of the affected patient (Kaufer et al. 1998; Donaldson, Tarrier, and Burns 1998; Fuh et al. 2001; Mourik et al 2004; Buhr, Kuchibhatla, and Clipp 2006; Aarsland et al. 2007).

Such disturbances also pose a quandary for clinicians as their etiology remains poorly understood and effective treatment options remain few. Behavioral and psychological impairments in dementia may also hinder appropriate treatment of other medical con­ditions, further frustrating clinicians and families while putting patients at greater medical risk.

The focus of this post will be to provide a framework for the greater understanding of the changes occurring in the neurotransmitter systems of the brain and how they relate to clinical symptom manifestations in dementia, as well as possible treatment approaches. Since Alzheimer’s dementia (AD) constitutes an estimated 60-80% of all diagnosed demen­tias, it will serve as the model for the discussion.