Over time, untreated major depressive disorder (MDD) changes a person’s brain, according to brain imaging research published online in The Lancet Psychiatry.
The study used positron emission tomography (PET) to measure translocator protein (TSPO), a marker of brain inflammation, in 25 people with more than a decade of MDD, 25 people with less than a decade of MDD, and 30 people without depression.
Compared to people with less than a decade of MDD, patients who had the disorder for more than a decade had TSPO levels nearly 30% higher in different brain regions, indicating significantly more brain inflammation, researchers reported. Brain inflammation among patients with more than a decade of MDD was also higher than in people without depression.
“Greater inflammation in the brain is a common response with degenerative brain diseases as they progress, such as with Alzheimer’s disease and Parkinson´s disease,” said study senior author Jeff Meyer, PhD, of the Centre for Addiction and Mental Health (CAMH) in Toronto, Canada.
Dr. Meyer and coauthors said the findings suggest long-lasting MDD is a progressive—not a static—condition, and may therefore require a different type of treatment. The researchers are investigating medications that target inflammation for patients with this later stage of illness.
Setiawan E, Attwells S, Wilson AA, et al. Association of translocator protein total distribution volume with duration of untreated major depressive disorder: a cross-sectional study. The Lancet Psychiatry. 2018 February 26;[Epub ahead of print].