The need for an integrated biopsychosocial approach to research on successful aging.

Successful aging is defined not by longevity alone but also by sufficient well-being (in multiple domains) to sustain a capacity for functioning adequately in changing circumstances. The determinants of such well-being and functional status are manifold and include the genetic endowment, physical environment, social environment, population and individual responses to challenges, the occurrence of disease, availability and effectiveness of health care, and personal prosperity. In the face of such complexity, scientific approaches to the phenomena associated with successful aging should be appreciative and wholistic as well as reductionistic. Such a "natural science" of aging will be required to uncover and use information about linear, cause-and-effect phenomena, as well as about higher-order emergent patterns that are of relevance to the health of elderly persons, such as "resilience" and "generativity." Taken as a whole, this multimethod research agenda will truly express an integrated biopsychosocial approach to research on successful aging.