Major depressive disorder tied to increased peripheral inflammation
C-reactive protein (CRP) levels appear to be elevated in patients with major depressive disorder (MDD) and even more so in those who are resistant to treatment, a study has found.
The study included 102 treatment-resistant patients with MDD presently experiencing depression (mean age 36.5 years; 70.6 percent female), 48 treatment-responsive patients with MDD not presently experiencing depression (mean age 35.9 years; 66.7 percent female), 48 patients with untreated MDD (mean age 35.1 years; 64.6 percent female) and 54 healthy volunteers (mean age 34.2 years; 68.5 percent female).
Researchers evaluated high-sensitivity CRP in peripheral venous blood, body mass index (BMI), depression, anxiety and childhood trauma. They estimated group differences and used partial least squares (PLS) analysis to examine the relationships between CRP and specific clinical phenotypes.
BMI-corrected CRP was significantly higher in the treatment-resistant group (p= 0.007; Cohen's d, 0.47) but not significantly so in the treatment-responsive (d, 0.29) and untreated (d, 0.18) groups relative to the control group.
PLS showed an optimal two-factor solution that explained 34.7 percent of variation in clinical measures and 36.0 percent of variation in CRP. Clinical phenotypes such as vegetative depressive symptoms, BMI, state anxiety, and feeling unloved as a child or wishing for a different childhood were strongly associated with CRP. These phenotypes heavily weighted on the first PLS component.
The present data indicate that patients with MDD stratified for proinflammatory biomarkers, such as CRP, have a distinctive clinical profile potentially responsive to second-line treatment with anti-inflammatory drugs, researchers said.