Toward a threshold for subthreshold depression: an analysis of correlates of depression by severity of symptoms using data from an elderly community sample.

Purpose: The prevalence of depressive symptoms in elderly adults is high, yet the criteria to identify clinically significant depression may leave many elders undiagnosed and untreated. We explored the demographic and risk factor profiles of two groups, one with more severe depression and one with less severe depression.
Design and Methods: The data come from the Duke University Established Populations for Epidemiologic Studies of the Elderly (EPESE) baseline survey of 4,162 community-dwelling adults aged 65 or older.
Results: The prevalence of depression meeting criteria of the Center for Epidemiologic Studies-Depression scale (CES-D) and sub-threshold depression was 9.1% and 9.9%, respectively. In ordinal logistic regression, both CES-D and subthreshold depression were associated with impairment in physical functioning, disability days, poorer self-rated health, use of psychotropic medications, perceived low social support, female gender, and being unmarried.
Implications: Depression appears to exist along a continuum, with demographic and social and physical health predictors of subthreshold depression similar to predictors of depression as defined by the CES-D scale.