Brain Scans Reveal 4 Depression Subtypes
Using brain scans, researchers have identified 4 unique subtypes of depression based on distinct patterns of abnormal connectivity. Their findings appear online in Nature Medicine.
“The 4 subtypes of depression that we discovered vary in terms of their clinical symptoms but, more importantly, they differ in their responses to treatment,” said researcher Conor Liston, MD, an assistant professor of neuroscience and psychiatry at Weill Cornell Medicine in New York, New York.
“We can now predict with high accuracy whether or not a patient will respond to transcranial magnetic stimulation therapy, which is significant because it takes 5 weeks to know if this type of treatment works.”
The collaborative study included 1180 functional magnetic resonance imaging (fMRI) brain scans of both patients with clinical depression and healthy controls from across the country. Researchers from Weill Cornell Medicine and 7 other institutions analyzed the scans and identified biomarkers linked with depression by assigning statistical weights to abnormal brain connections. Next, they predicted the probability that the abnormal connections belonged to a particular subtype versus another.
The study showed that distinct patterns of abnormal connectivity in the brain differentiated the 4 subtypes and were linked with specific symptoms. Reduced connectivity in the brain region that regulates fear-related behavior and reappraisal of negative emotional stimuli, for example, was most severe in subtypes 1 and 4, which demonstrated increased anxiety.
Researchers believe their findings may be useful for identifying patients most likely to benefit from targeted neurostimulation therapies.
Historically, efforts to characterize depression by looking at groups of symptoms that tend to co-occur and then testing neurophysiological links have produced inconsistent results, they explained.
"Depression is typically diagnosed based on things that we are experiencing, but as in election polling, the results you get depend a lot on the way you ask the question," Dr. Liston said. "Brain scans are objective."