Frailty: A Multidimensional Biopsychosocial Syndrome.

The original conceptual landscape of frailty has evolved into a complex, multidimensional biopsychosocial syndrome. This has broadened the field to now include social and behavioral scientists and clinicians from a wide range of specialties. This article aims to provide an updated overview of this conceptual change by examining the emerging definitions of physical, cognitive, social, and psychological frailty; the tools used for diagnosis and assessment of these domains; the epidemiology of the domains; their pathogenesis, risk factors, and course; frameworks for prevention and treatment; and unresolved issues affecting the field.