Functional disability and depressive symptoms: longitudinal effects of activity restriction, perceived stress, and social support.

OBJECTIVES: This longitudinal study investigates how activity restriction, perceived stress, and social support affect the relationship between functional disability and depressive symptoms.
METHOD: This longitudinal study of a Taiwan population analyzed a nationally representative sample of 1268 subjects aged 60 years and over. Path analysis was used to assess interrelations among functional disability, activity restriction, perceived stress, social support, and depressive symptoms over time.
RESULTS: The analytical results supported the following relationships: (a) high functional disability were associated with high activity restriction, low social support, and high perceived stress over time, (b) high functional disability, high activity restriction, low social support, and high perceived stress were associated with high levels of depressive symptoms over time, (c) among the four factors, perceived stress exerted the strongest cross-sectional and longitudinal effect on depressive symptoms, and (d) the significant effect of prior functional disability on subsequent depressive symptoms substantially contributed to indirect changes in activity restriction, perceived stress, and social support between waves.
CONCLUSION: The findings indicate that functional disability may contribute to subsequent depressive symptoms by reducing activities and social support. Decreased activities and social support increased perceptions of stress, which then increased depressive symptoms during the 8-year follow-up study.