Suicidal Thoughts Linked With Brain Inflammation

October 3, 2017

In patients with major depressive disorder, neuroinflammation may contribute to the risk of suicidal thoughts and behavior, suggests a new study published online in Biological Psychiatry.

Researchers came to their findings after assessing neuroinflammation in 14 medication-free patients experiencing a major depressive episode of moderate to severe severity. Brain imaging revealed elevated levels of translocator protein, an inflammatory marker of microglial activation—which is itself a sign of neuroinflammation, in patients with suicidal thoughts.

“This paper is an important addition to the view that inflammation is a feature of the neurobiology of a subgroup of depressed patients, in this case the group with suicidal ideation,” said John Krystal, MD, editor of Biological Psychiatry. “This observation is particularly important in light of recent evidence supporting a personalized medicine approach to depression, i.e., that anti-inflammatory drugs may have antidepressant effects that are limited to patients with demonstrable inflammation.”

The Ancient, Genetic Link Between Inflammation and Depression

The study found evidence of immune activation was most prominent in the anterior cingulate cortex of the brain, a region involved in mood regulation and implicated in the biological origin of depression. Other increases in microglial activation, although smaller, were found in the insula and prefrontal cortex.

The findings, said researcher Peter Talbot, MD, of the University of Manchester in England, “emphasize the importance of further research into the question of whether novel treatments that reduce microglial activation may be effective in major depression and suicidality.”

—Jolynn Tumolo


Holmes SE, Hinz R, Conen S, et al. Elevated translocator protein in anterior cingulate in major depression and a role for inflammation in suicidal thinking: a positron emission tomography study. Biological Psychiatry. 2017 August 12;[Epub ahead of print].

Study links brain inflammation to suicidal thinking in depression [press release]. Philadelphia, PA: Elsevier; September 21, 2017.