The importance of subsyndromal depression in older primary care patients: Prevalence and associated functional disability

OBJECTIVE: Existing diagnostic categories for depression may not encompass the majority of older people suffering clinically significant depressive sy mptoms. We have described the prevalence of subsyndromal depressive symptom s and tested the hypothesis that patients with subsyndromal depression have greater functional disability and general medical burden than nondepressed subjects but less than patients with diagnosable depressions. METHODS: Subjects were 224 patients, aged 60 years and older, recruited fro m private internal medicine offices or a family medicine clinic. Validated measures of psychopathology, medical burden, and functional status were use d. The subsyndromal depression group was defined by a score of more than 10 on the Hamilton Rating Scale for Depression and by the absence of major or minor depressive disorder. Analyses included multiple regression technique s to determine the presence of group differences adjusted for demographic c ovariates. RESULTS: Subsyndromal depression was common (estimated point prevalence of 9.9% compared with 6.5% for major depression, 5.2% for minor depression, an d .9% for dysthymic disorder), associated with functional disability and me dical comorbidity to a degree similar to major or minor depression, and oft en treated with antidepressant medications. CONCLUSIONS: Although depressive conditions are common and are associated w ith considerable functional and medical morbidity in older primary care pat ients, many patients with clinically significant depressive symptoms are no t captured by criteria-based syndromic diagnostic categories. Future work s hould include intervention studies of subsyndromally depressed older person s as well as attention to the course and biopsychosocial concomitants of di agnosable and subsyndromal depressions in this population.