Scientists have identified in the brain a network specific to the reduction of gray matter, common to all diagnoses of mental pathologies: the transdiagnostic network.
- Mental disorders are defined as a major alteration in cognitive state, emotion regulation or behavior.
- Researchers have discovered a network specific to gray matter decreases, common to all mental illness diagnoses.
- The identification of this network, called the transdiagnostic network, should enable new advances in the understanding and management of mental pathologies.
According to the World Health Organization (WHO), one in eight people in the world – or 970 million people – lived with a mental illness in 2019. They can be defined as a significant alteration in a person’s cognitive state, emotion regulation or behavior. There are several different mental disorders.
Reduction of gray matter in certain areas of the brain
A team of researchers wanted to know the regions of the brain associated with several of these mental disorders. They chose six major disorders: depression, anxiety, schizophrenia, bipolar disorder, substance abuse and obsessive compulsive disorder (OCD).
To study them, they analyzed the brain data of 15,000 people. Some did not suffer from mental illness and others did. Their findings were published in the journal Nature Human Behavior.
In people with mental illness, certain areas of the brain are affected. These are the anterior cingulate, a region linked to emotions, and the insula, an area associated with self-awareness. In these areas, gray matter is reduced. Furthermore, these regions of the brain are also affected by neurodegenerative diseases.
Injuries on the transdiagnostic network increase the risk of mental illnesses
To better understand how mental disorders specifically affect the brain, researchers analyzed the connectome, a map of human brain connections. They thus discovered a network specific to the reduction of gray matter, common to all mental illnesses, this is the transdiagnostic network. What matters in mental illness is therefore not the result of the reduction in gray matter but the path taken by this alteration.
To continue their study, the scientists analyzed the medical records of 194 Vietnam veterans who had brain injuries. The goal was to find out if the affected area had an impact on mental disorders diagnosed in veterans. The results were convincing: those who had been injured in the transdiagnostic network were more likely to suffer from psychiatric disorders.
Common points between psychiatric and cerebral disorders
However, researchers suggest that the reduction in gray matter in the anterior cingulate and insula may not be the cause of mental illness – contrary to what was previously thought – but rather a consequence. “We found that damage to these regions—the anterior cingulate and insula—correlated with less psychiatric illness, so atrophy of this cingulate and insula may be a consequence or compensation for psychiatric illness rather than ‘a cause of it’details Joseph J. Taylor, one of the authors, in a communicated.
Scientists hope that the discovery of this transdiagnostic network specific to psychiatric illnesses will lead to new research and advances in the understanding and treatment of mental disorders.
“Psychiatric disorders are brain disorders, and now we are just beginning to have the tools to study and modulate their underlying circuitsconcludes Joseph J. Taylor. There may be more in common between these disorders than we initially thought.”
