Elevated levels of C-reactive protein, a marker of inflammatory disease, appear to be associated with an increased risk of psychological distress and depression, according to a new study.
Previous studies have suggested that low-grade systemic inflammation may contribute to the development of depression, which is a leading cause of disability. C-reactive protein (CRP) is a commonly used marker of inflammation, and inflammatory disease is suspected when CRP levels exceed 10 mg/L.
A research team led by Marie Kim Wium-Andersen, M.D., of Herlev Hospital and Copenhagen University Hospital in Denmark, examined whether elevated plasma levels of CRP were associated with distress and depression.
Researchers analyzed CRP levels using data from two general population studies in Copenhagen, which included 73,131 people between the ages of 20 and 100.
The study’s main finding was an association of elevated CRP levels with an increased risk for psychological distress and depression in the general population.
For self-reported antidepressant use, the odds ratio was 1.38 for CRP levels of 1.01 to 3 mg/L, 2.02 for 3.01 to 10 mg/L, and 2.7 for greater than 10 mg/L compared with 0.01 to 1 mg/L. For prescription of antidepressants, the corresponding odds ratios were 1.08, 1.47 and 1.77, respectively; for hospitalization with depression they were 1.30, 1.84 and 2.27.
Other analyses suggest that increasing CRP levels also were associated with increased risk for hospitalization with depression, according to the study results.
The scientists say more research is needed, but note the results of this study “support the initiation of intervention studies to examine whether adding anti-inflammatory drugs to antidepressants for treatment of depression will improve outcome.”
The study was published in Archives of General Psychiatry’s Online First.