There is an association between elevated plasma levels of C-reactive protein (CRP) and an increased risk for psychological distress and depression in the general population, according to a study published online Dec. 24 in theArchives of General Psychiatry.CRP is a commonly used marker of inflammatory disease when CRP levels exceed 10 mg/L. Previous studies, though, had yielded conflicting results regarding the strength of the association between CRP levels and psychological distress and depression, for which an inflammatory-related pathogenic mechanism is not understood. For the study the researchers examined data on 73,131 men and women (aged 20 to 100 years) derived from two general population cohorts (the Copenhagen General Population and the Copenhagen City Heart studies). They analyzed CRP levels in clinically relevant categories of psychological distress and depression. Psychological distress was measured using self-reported symptoms. Depression was ascertained using self-reports of anti-depressant uses, national prescription registries, and hospital discharge diagnoses of depression. The researchers found that CRP levels were associated with increasing risk for the self-reported symptoms of psychological distress of “not accomplishing much” and “wanting to give up.” Increasing CRP levels were also associated with a significantly increasing risk for self-reported use of anti-depressants as well as for increasing odds of using of prescription anti-depressants for at least six months, and an increasing risk for hospitalization due to depression. Contrary to previous studies, these associations did not disappear when adjusting for body mass index and chronic disease status. “The results also support the initiation of intervention studies to examine whether adding anti-inflammatory drugs to antidepressants for treatment of depression will improve outcome,” wrote lead author Marie Kim Wium-Andersen, M.D., from University of Copenhagen in Denmark.