Levels of C-reactive protein (CRP) in patients with schizophrenia, unipolar depression and bipolar disorder.

OBJECTIVE

C-reactive protein (CRP) is the major acute-phase plasma protein. Studies show that patients with various mental disorders have elevated levels of CRP. The aim of the study was to determine differences in CRP serum level in patients with acute schizophrenia, unipolar depression, bipolar depression and bipolar mania.

METHOD: Serum level of CRP was measured in 950 Caucasian inpatients (589 women, 62.0%; mean age 50.3 years).

RESULTS

Mean concentration of CRP in study groups was: schizophrenia (n = 485) 5.30 mg/l, unipolar depression (n = 319) 5.61 mg/l, bipolar disorder (n = 146) 4.65 mg/l, bipolar depression (n = 114) 3.82 mg/l and bipolar mania (n = 32) 7.36 mg/l. There was no difference for CRP levels between patients with schizophrenia, unipolar depression, bipolar depression and bipolar mania (P = 0.58). The overall rate of being above the high level of CRP (set at 3.0 mg/l) was 35.7% for schizophrenia, 38.6% for unipolar depression, 40.4% for bipolar disorder, 40.4% for bipolar depression and 40.6% for bipolar mania. There were no significant differences in the risk of having high level of CRP between the clinical groups. The rate of patients being above high level was higher in women. We also found that in whole study group CRP level was positively correlated with age (P = 0.002).

CONCLUSIONS

Although there is no statistically significant difference in CRP serum level between patients with schizophrenia, unipolar depression, bipolar depression and bipolar mania, our results show that more than one-third (37.4%) of all subjects had CRP level > 3 mg/l, which is the cut-off point for high cardiovascular risk.