C-Reactive Protein in Bipolar Disorder and Unipolar Depression

This study aimed to explore the role of C-reactive protein (CRP) in the pathological mechanism and differential diagnoses of bipolar disorder (BD) and unipolar depression (UD). We tested serum CRP levels of 176 BD and 86 UD patients, and 82 healthy controls (HCs), at acute and remission phases. In the acute phase, CRP levels were higher in BD than in UD patients and HC, and lower in UD patients than in HC. The CRP levels of BD patients in a manic episode were higher than those of HC; in a depressive or mixed episode, they were comparable to those of HC. The CRP levels of BD and UD patients during an acute depressive episode yielded an area under the curve of 0.676. CRP may be a state marker of acute manic episodes in BD and acute depressive episodes in UD, and a biomarker for distinguishing BD and UD.