Inflammation Connected to Risk of Major Depressive Disorder

There is a direct connection between inflammation and depression independent of genetic, health, and psychosocial factors, according to a recent study published in the American Journal of Psychiatry.

In this case-controlled study, levels of C-reactive protein, a marker for inflammation, along with genetic and phenotypic data from the UK Biobank were assessed in 26,894 participants with lifetime diagnosis of major depressive disorder and compared to 59,001 control subjects with no reported mental disorders or history of antidepressant medication.

Researchers factored the effects of age, sex, body mass index, and smoking habits on participants’ risk factors for major depressive disorder and used a linear regression model to assess if the polygenic risk score for major depression was associated with levels of C-reactive protein.

Cellular Aging Accelerated in Patients With Major Depressive Disorder

Additionally, they assessed if C-reactive protein levels still had an impact on the risk of depression after factoring in trauma, socioeconomic status, and health.

Levels of C-reactive protein were higher in patients with depression when compared to the control subjects.

While the association between depression risk and inflammation was reduced after adjusting for environmental and sociodemographic factors, a significant association between C-reactive protein levels and depression was found.

The polygenic risk score for major depressive disorder also showed a significant connection to C-reactive protein levels. However, the findings were insignificant after factoring for body mass index and smoking habits.

“Moreover, the association between depression and increased inflammation even after full adjustment indicates either the presence of yet unknown or unmeasured psychosocial and clinical confounding factors or that a core biological association between depression and increased inflammation exists independently from confounders,” concluded Maria C.  Pitharoul, M.Sc, and co-researchers.

—Erin McGuinness

Reference:

Pitharouli MC, Hagenaars SP, Glanville KP, et al. Elevated c-reactive Protein in patients with depression, independent of genetic, health, and psychosocial factors: results from the UK biobank. American Journal of Psychiatry. 2021 May 14;[Epub ahead of print].