Low-grade inflammation differentiates between symptoms of apathy and depression in community-dwelling older individuals

• Published in: International psychogeriatrics Vol. 27; no. 4; p. 639
• Main Authors: Eurelings, Lisa S M, Richard, Edo, Eikelenboom, Piet, van Gool, Willem A, Moll van Charante, Eric P
• Format: Journal Article
• Language: English
• Published: England 01-04-2015
• Subjects: Aged - psychology; Apathy - physiology; C-Reactive Protein - analysis; Cross-Sectional Studies; Depression - physiopathology; Female; Humans; Independent Living - psychology; Independent Living - statistics & numerical data; Inflammation - psychology; Logistic Models; Longitudinal Studies; Male; Psychiatric Status Rating Scales; cardiovascular disease
• ISSN: 1741-203X
• DOI: 10.1017/s1041610214002683

Systemic low-grade inflammation has repeatedly been associated with depression in old age, but the relationship with apathy is less clear. The present study assessed whether C-reactive protein (CRP) is differentially associated with symptoms of apathy and depression.
A population-based cohort study was carried-out. At baseline and after two and four years of follow-up, CRP levels were assessed and symptoms of apathy and depression were measured using the 15-item Geriatric Depression Scale. Logistic regression analysis was used to investigate the cross-sectional and longitudinal associations of CRP with symptoms of apathy and depression.
Two thousand forty-seven community-dwelling participants (70-78 years) without a history of cardiovascular disease or stroke were studied. A cross-sectional association was found between CRP and apathy symptoms at three time points (odds ratio (OR) per natural log unit increase in CRP: baseline visit = 1.40, 95% CI = 1.12-1.75; two-year follow-up visit = 1.62, 95% CI = 1.17-2.25; four-year follow-up visit = 1.51, 95% CI = 1.03-2.21). This did not change after adjustment for demographics and depressive symptoms, and was slightly attenuated after adjustment for cardiovascular risk factors. No cross-sectional association was found with depressive symptoms. Baseline CRP did not predict incident apathy or depressive symptoms during four years of follow-up.
Increased CRP levels are associated with apathy symptoms but not with depressive symptoms. This suggests a differential effect of inflammation on apathy and depression. In older persons, symptoms of apathy may be a behavioral manifestation of concurrent low-grade inflammation.