Study links brain inflammation to suicidal thinking in depression

September 21, 2017, Elsevier
Credit: George Hodan/Public Domain

Patients with major depressive disorder (MDD) have increased brain levels of a marker of microglial activation, a sign of inflammation, according to a new study in Biological Psychiatry by researchers at the University of Manchester, United Kingdom. In the study, Dr. Peter Talbot and colleagues found that the increase in the inflammatory marker was present specifically in patients with MDD who were experiencing suicidal thoughts, pinning the role of inflammation to suicidality rather than a diagnosis of MDD itself.

"Our findings are the first results in living to suggest that this microglial activation is most prominent in those with suicidal thinking," said Dr. Talbot. Previous studies suggesting this link have relied on brain tissue collected from patients after death.

"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 Dr. John Krystal, 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."

In the study, first author Dr. Sophie Holmes and colleagues assessed inflammation in 14 patients with moderate-to-severe depression who were not currently taking any antidepressant medications. Immune cells called microglia activate as part of the body's inflammatory response, so the researchers used a brain imaging technique to measure a substance that increases in activated microglia.

The evidence for immune activation was most prominent in the , a brain region involved in mood regulation and implicated in the biological origin of depression, confirming the results of a previous study that first identified altered microglial activation in medication-free MDD patients. Smaller increases were also found in the insula and prefrontal cortex.

"The field now has two independent reports—our study and a 2015 report by Setiawan and colleagues in Toronto—showing essentially the same thing: that there is evidence for , more specifically microglial activation, in the brains of living patients during a major depressive episode," said Dr. Talbot.

This link suggests that among depressed patients, neuroinflammation may be a factor contributing to the risk for or behavior. According to Dr. Talbot, the findings "emphasise the importance of further research into the question of whether novel treatments that reduce microglial activation may be effective in major depression and suicidality."

Explore further: Study reveals why some depressed patients have blood inflammation

More information: Sophie E. Holmes 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). DOI: 10.1016/j.biopsych.2017.08.005

Related Stories

Study reveals why some depressed patients have blood inflammation

May 5, 2016
A new King's College London study reveals why some - but not all - people have depression that appears to be caused by blood inflammation.

Brain inflammation linked to depression in multiple sclerosis

July 7, 2016
Patients with multiple sclerosis have higher rates of depression than the general population, including people with other life-long disabling diseases. Symptoms of multiple sclerosis arise from an abnormal response of the ...

New biological evidence reveals link between brain inflammation and major depression

January 28, 2015
A new study by the Centre for Addiction and Mental Health (CAMH) found that the measure of brain inflammation in people who were experiencing clinical depression was increased by 30 per cent. The findings, published today ...

Women and men may have different bipolar disorder biomarkers

July 11, 2017
Men and women react differently to compounds associated with immune system response to bipolar disorder, according to an international team of medical researchers. The findings suggest that bipolar disorder could one day ...

Inflammation attacks brain's reward center

February 2, 2016
A new study by Neil Harrison and colleagues published in Biological Psychiatry suggests that a brain reward center, the striatum, may be directly affected by inflammation and that striatal change is related to the emergence ...

The brain may show signs of aging earlier than old age

March 18, 2016
A new study published in Physiological Genomics suggests that the brain shows signs of aging earlier than old age. The study found that the microglia cells—the immune cells of the brain—in middle-aged mice already showed ...

Recommended for you

People with prosthetic arms less affected by common illusion

January 22, 2018
People with prosthetic arms or hands do not experience the "size-weight illusion" as strongly as other people, new research shows.

Study of learning and memory problems in OCD helps young people unlock potential at school

January 22, 2018
Adolescents with obsessive-compulsive disorder (OCD) have widespread learning and memory problems, according to research published today. The findings have already been used to assist adolescents with OCD obtain the help ...

Intensive behavior therapy no better than conventional support in treating teenagers with antisocial behavior

January 19, 2018
Research led by UCL has found that intensive and costly multisystemic therapy is no better than conventional therapy in treating teenagers with moderate to severe antisocial behaviour.

Babies' babbling betters brains, language

January 18, 2018
Babies are adept at getting what they need - including an education. New research shows that babies organize mothers' verbal responses, which promotes more effective language instruction, and infant babbling is the key.

College branding makes beer more salient to underage students

January 18, 2018
In recent years, major beer companies have tried to capitalize on the salience of students' university affiliations, unveiling marketing campaigns and products—such as "fan cans," store displays, and billboard ads—that ...

Inherited IQ can increase in early childhood

January 18, 2018
When it comes to intelligence, environment and education matter – more than we think.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.