A new study has revealed that many mental disorders share a common structure in the brain. Six conditions were examined and found to be connected by the loss of gray matter in three specific areas related to cognitive functions such as self-control.
The research, published in JAMA Psychiatry, took the form of a meta-analysis of structural neuroimaging studies involving addiction, anxiety, bipolar disorder, depression, obsessive-compulsive disorder and schizophrenia.
“During the past several decades, psychiatry has focused on establishing diagnostic categories based on clinical symptoms,” write the authors. “Accordingly, most neuroimaging studies have compared brain structure or function in patients with a single, specific diagnosis with healthy participants.”
However, both clinical and genetic analyses have observed similarities among several different disorders, suggesting that there could be an underlying neurobiological link between forms of mental illness.
The authors state that there is a “disconnection” between psychiatric disease classification and rapidly emerging biological findings, emphasizing the need for this research.
Madeleine Goodkind, PhD, and coauthors set about reviewing structural neuroimaging studies for six different mental disorders from three large data sets. The analysis included 193 peer-reviewed articles, involving 7,381 patients and 8,511 matched healthy control patients.
The studies all used an imaging technique called voxel-based morphometry (VBM), chosen by the authors as it assesses the entire brain, uses standardized methods and has been widely used among major psychiatric diagnoses.
Across the six psychiatric diagnoses, the authors found gray matter loss occurred in three regions of the brain – the dorsal anterior cingulate (dACC), the right insula and the left insula.
Analysis of these regions of the brain in the healthy participants revealed they form an interconnected network associated with executive functioning – the management of cognitive processes such as decision making, reasoning and self-control.
The authors write that this finding “helps ground a transdiagnostic understanding of mental illness in a context suggestive of common neural mechanisms for disease etiology and/or expression.”
“Our findings suggest that a general mapping exists between a broad range of symptoms and the integrity of an anterior insula/dACC-based network across a wide variety of neuropsychiatric illnesses,” conclude the authors.
Senior author of the study Dr. Amit Etkin told Live Science that the discovery of a common neural structure for these psychiatric disorders will allow therapies for certain disorders to be used to treat others.
Computer cognitive training is one such therapy. It is currently a promising form of treatment for schizophrenia, and now it could potentially be put to use in the treatment of other conditions.
Future research projects will investigate whether there are also similarities in brain activity across different psychiatric diagnoses. In addition, the effects of noninvasive brain stimulation to the three brain regions will be studied, in order to assess whether this could form the basis of a treatment for these disorders.
The authors state “the fact that common structural changes are seen despite potentially differing etiologies raises the possibility that some interventions that target the anterior insula and dACC may prove of broad use across psychopathology.”
In another study examining reductions in gray matter volume, researchers revealed that psychopathic violent offenders may be unable to fully process punishment due to abnormalities in certain regions of the brain.