Long-term patterns of depression and associations with health and function in a panel study of rheumatoid arthritis.

Long-term patterns of depression, and associations with health and function were examined among 1115 individuals with rheumatoid arthritis, using 18 years of panel data, summarized in 9653 interviews. Depression was defined by scores on the Geriatric Depression Scale (6 or above). Participants were classified, using cluster analysis, into three distinct patterns of depression over repeated assessments: nondepressed (65.8%), intermittent (25.2%), and chronic (9.0%). GEE analyses assessed outcomes over time as a function of patterns of depression; controlling for demographic and clinical factors. Results indicated that patterns of depression had significant adverse effects on health and function over time.