Widely incriminated during severe depression and suicide, inflammation of certain regions of the brain would be poorly controlled in depressed people who commit suicide.
A new study, published in the American Journal of Psychiatry, very convincingly associates the inflammation in the brains of people who are depressed to suicide and above all, it seems to show that it would be a disorder of the regulation of this inflammation which would be in question and that this disorder is of "epigenetic" origin, that is, the result of a "toxic" environment.
Severe depression, suicide and inflammation
Inflammation of the brain is increasingly implicated in psychiatric illnesses, and in particular their severe and resistant forms of treatment. It is an inflammation that concerns, of course, the nerve cells, but especially the glial cells that surround the nerve cells, which feed them and which probably have many other functions still unknown today.
The inflammation proteins, the "cytokines", whose production seems abnormal during severe depression, are therefore found in the brains of depressed and suicidal patients, but also in their entire body and in white blood cells.
An analysis of TNF-alpha in the brain
The authors of the study were interested in a key protein of the inflammatory cascade, TNF-alpha, and messenger RNAs of TNF-alpha, in the brains of depressed people who died by suicide.
The researchers analyzed both TNF-alpha levels in brain regions that are related to depression and suicide (dorso-lateral prefrontal cortex) in depressed people who died by suicide and other depressed people died of a cause other than suicide.
The genetic side of the study was performed by analyzing 3 polymorphisms in the chromosome region that is related to TNF-alpha synthesis.
A disorder of the regulation of inflammation
TNF-alpha is found at high concentrations in the dorso-lateral prefrontal cortex of the brains of depressed people who die by suicide, but also in depressed people who died in a cause other than suicide.
On the other hand, the levels of messenger RNAs responsible for the secretion of TNF-alpha are only high in the brains of depressed people who have died by suicide. This abnormality is also found in the blood of people who have suicidal thoughts.
It also appears that TNF-alpha inhibitors fail to bind to TNF-alpha in the brain of suicidal depressed patients, a factor in favor of a defect in the regulation of inflammation that would be specific to the depressed brain. suicidal. In this study, there is no genetic abnormality in the TNF-alpha regulatory pathway. It is rather a complex epigenetic influence.
This study provides a better understanding of why some people are at greater risk of suicide than others. Above all, it opens the door to a screening of those most at risk of suicide, or even offer them a specific "anti-inflammatory" treatment in addition to their antidepressant treatment.