Abstract
Purpose: The aim of this study was to investigate the association between depressive symptoms severity and amplitude of diurnal variations in depression symptoms in patients with chronic obstructive pulmonary disease (COPD).
Design: Prospective, observational proof-of-concept study.
Methods: Fourteen participants with moderate/severe COPD completed a 20-item Center for Epidemiologic Studies Depression Scale (CES-D) estimating depressive symptoms severity. Throughout one week, the four-item very short version of the CES-D was completed every day in the morning, afternoon, and evening.
Findings: Strong positive correlations were observed between depressive severity and the mean range of diurnal variations in positive (r = .61) and depressed affects (r = .67), somatic complaints (r = .82), and disturbed interpersonal relationships (r = .71).
Conclusion: In COPD patients, a greater diurnal variation in depression symptoms was associated with greater depression severity. This relationship seems independent of COPD severity.
Clinical Relevance: Diurnal variation in the symptoms of depression is a new method of identifying depression severity in COPD.