Researchers have discovered a similar pattern of grey-matter loss in the brain across a broad range of psychiatric disorders, suggesting that mental illnesses with differing symptoms could arise from the same neurological basis. Their findings challenge the assumption of differentiating mental disorders by symptoms rather than by brain pathology.
Dr. Amit Etkin of Stanford University, the study’s senior author, and his research team examined and compared MRI data from 193 separate studies. Their meta-analysis looked at a total of 7,381 patients over six psychiatric diagnoses: schizophrenia, bipolar disorder, major depression, addiction, obsessive-compulsive disorder and anxiety-related disorders. They used the brain MRIs of 8,511 healthy patients as a control group.
Across the patients with mental illness, the researchers found decreased volumes of gray matter in three separate but interconnected brain regions: the left and the right anterior insula and the dorsal anterior cingulate. Previous research has shown that these three brain regions seem to activate simultaneously and linked them to higher level cognition and executive actions. Grey matter is the neurological tissue that processes information.
“In many of these published studies we reviewed, researchers have tended to interpret their biological findings in terms of the one disorder they’re focusing on,” said Etkin. “We tried to ask a basic question that hasn’t been asked: Is there any common biological basis for mental illness?”
“I wouldn’t have expected these results,” said Dr. Thomas Insel, director of the National Institute of Mental Health, who was not a part of the study. “I’ve been working under the assumption that we can use neuroimaging to help classify the different forms of mental illness. This makes it harder.”
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