Subsyndromal depression: An impact on quality of life?

Objective: The objective of this study was to demonstrate the association between quality of life and subsyndromal depression in a primary care clinic in a Brazilian sample. Methods: This was a cross-sectional study. The cases were divided into three groups according to the severity of depressive symptoms: 1) subjects with major depressive disorder; 2) subjects with subsyndromal depression; 3) subjects without depressive symptoms - controls. The participants completed the World Health Organization Instrument to Assess Quality of Life (WHOQOL-BREF), the Quality of Life - Depression (QLDS), the Centers for Epidemiologic Studies - Depression instrument (CES-D), and the Composite International Diagnostic Interview (CIDI). Results: The sample consisted of 438 primary care users (35.2% of them had subsyndromal depression). The subjects with major depression presented the worst impairment of quality of life, which was measured by the WHOQOL-BREF and the QLDS. The patients with subsyndromal depression had a smaller impact on their quality of life and the subjects without depression presented an even lower impact. The hierarchical linear regression involving demographic variables and the severity of depressive symptoms showed that the severity of depression was the variable with higher correlation with quality of life dimensions, presenting increased variation in the domains (from 9% to 24%). Conclusions: The results suggest that subsyndromal depression causes impairment of the quality of life in primary care patients of a Brazilian sample. (C) 2006 Elsevier B.V. All rights reserved.