High Inflammation Linked to Depression Symptoms

Previous research has discovered that approximately one third of people with depression have high levels of inflammation markers in their blood. A recent study suggests that this type of high-inflammation depression affects the reward circuit in the brain and also reduces motivation and goal-directed motor behavior.

Participants in the study included 48 people with depression. The researchers took images of their brains during a period when they had not been taking any antidepressants, anti-inflammatory drugs, or other medications for at least four weeks. The researchers also measured C-reactive protein levels on multiple visits.

High levels of the inflammatory marker C-reactive protein were associated with decreased communication between the regions of the brain responsible for motivation and reward. Active connectivity between those parts of the brain where noted in people with low C-reactive protein levels.

The researchers also found that high levels of C-reactive protein were associated with patient reports of anhedonia or the inability to get pleasure from normal, every day activities such as eating or spending time with loved ones.

The correlation between high C-reactive protein depression symptoms remained statistically strong even after correcting for BMI and other variables such as age.

Researchers from Emory University School of Medicine and Winship Cancer Institute conducted the study. It was published online ahead of print on November 10, 2015, in Molecular Psychiatry.