Activity restriction mediates the association between pain and depressed affect: a study of younger and older adult cancer patients.

Associations are reported frequently among pain, functional disability, and symptoms of depression. The purpose of this longitudinal study was to further clarify relations among these variables. In 268 younger (ages 30-64) and older (ages 65-90) cancer outpatients, cross-sectional analyses replicated previous findings showing that effects of pain on symptoms of depression are mediated by functional disability. Longitudinal analyses revealed that as pain increased over time, so did activity restriction, which in turn predicted increases in depressed affect. Comparative analyses indicate that restriction of routine activities that are due to illness and pain may be more distressing to individuals less than 65 years of age than to those 65 years of age or older. The results suggest that older persons are less distressed by restricted activities because of lower expectations about functional status and more experience with illness and disability.