The neuropsychiatric burden of neurological diseases in the elderly.

Psychogeriatrics began as an extension of psychiatry, with an emphasis on the unique manifestation of psychiatric disorders in the elderly. Early in the history of psychogeriatrics there was an emphasis on late-onset or late-enduring depression; paraphrenia and late-onset psychotic disorders; the late-life phases of schizophrenia; and anxiety and substance abuse disorders in the elderly. Growing recognition of the increasing frequency of Alzheimer’s disease (AD) in the course of aging and the high prevalence of behavioral disturbances in patients with AD led psychogeriatricians to study the diagnosis and management of this disorder. Increasing recognition that brain dysfunction is manifested by behavioral as well as cognitive and functional decline, and the evolution of appropriate instrumentation for detecting behavioral changes in patients with neurological disorders has produced an enhanced awareness of the neuropsychiatric burden of other neurologic diseases in the elderly. The high rate of behavioral changes and neuropsychiatric symptoms across a range of neurological disorders in aged individuals requires engagement of the psychogeriatric community in the management of these conditions. The behavioral and psychological symptoms of neurological disorders are under-recognized and under-treated. These symptoms cause marked patient and caregiver distress, contribute to institutionalization of affected individuals, and are detrimental to quality of life (Shin et al., 2005; Cummings, 2003). Behavioral symptoms in neurological disorders may respond to treatment with psychotropic agents or anti-dementia compounds and recognition of the behavioral symptoms may assist in diagnosis and differential diagnosis of dementia. The behavioral phenotype may eventually assist in choosing and guiding disease-modifying therapies.