State of the Science: Apathy As a Model for Investigating Behavioral and Psychological Symptoms in Dementia.

Apathy is one of the most common and pervasive of the behavioral and psychological symptoms of dementia (BPSDs). Apathy has profound consequences for morbidity, mortality, and caregiver burden. Treatment of apathy has been hindered because of poor understanding of the mechanisms underlying this heterogeneous syndrome. Research has demonstrated that apathy is associated with disruption of the frontal-striatal system in individuals with neurodegenerative disease. As with other BPSDs, these neural mechanisms alone do not completely account for the syndrome; individual, caregiver, and environmental factors also contribute to apathy. In this article, we modify a current conceptual model of the factors contributing to BPSDs to examine determinants of apathy. This integrative model provides a more complete and theoretically informed understanding of apathy, allowing for greater insight into potential targets for research, intervention, and care. We end by proposing an agenda for moving the science of BPSDs in general, and apathy in particular, forward.