A systemic-wholistic approach to differential aging: longitudinal findings from the Berlin Aging Study.

Wholistic perspectives on differential change focus on multiple-indicator information at a person level. They supplement the modeling of average trajectories at a variable level. The authors extended cross-sectional work in the Berlin Aging Study (J. Smith & P. B. Baltes, 1997) to 6-year longitudinal cluster analyses (n = 132). At baseline, 3 subgroups were identified with distinct within-person psychological profiles across cognitive, personality, and social integration constructs. Over time, highly similar subgroup profiles were found, and about two thirds of the participants could be classified as remaining in the same subgroups. Baseline subgroups differed in level and slope of change and in 2 outcomes, well-being and mortality. Independent of subgroup membership, subgroup-to-subgroup change was associated with greater decline and predicted poststudy mortality. These findings demonstrate the usefulness of a wholistic approach for long-term prediction of outcomes and within-person systemic variability.