According to a recent large study, people with depression have higher levels of inflammation in their bodies than those without depression, regardless of genetics, environmental aspects, medical history or unhealthy lifestyle choices.
The study analyzed blood samples, genetic data, and both physical and mental health of 85.895 people and found that depressed participants had raised C-reactive protein (CRP) levels in their blood compared to non-depressed participants. CRP is a measure used to define an inflammation level in the body, which is not only responsible for fighting infection but also has an important role in regulating behavior.
In further analysis the researchers adjusted the data by removing the possible explanation factors for the relationship between depression and inflammation, such as socioeconomic background, ill health, unhealthy habits as well as genetic predisposition to immune dysfunction. It turned out that the abovementioned factors only partially give an explanation and that there is may be another key biological process behind the increased inflammation in depressed people.
It is worth mentioning, that the greater the genetic risk for depression was, the greater the level of inflammation. However, the researchers believe that the genetic contribution to increased inflammation in depression comes mostly from eating and smoking habits rather than from an genetic predisposition to immune dysfunction.
Curious? Here is the source: https://ajp.psychiatryonline.org/doi/10.1176/appi.ajp.2020.20060947