A specific brain abnormality may indicate a person’s general risk for mental illness, according to a new study at Duke University.
The signature abnormality involves a reduced efficiency between the brain’s visual areas and certain networks important for integrating sensory information and suppressing distracting information. This reduced efficiency is found among people at risk for various types of mental disorders.
“These patterns suggest that broad risk for mental illness may reflect subtle problems in how a person is able to integrate their thoughts, plans, and actions with their fundamental experience of the world, which in humans is principally represented by visual information,” said first author Maxwell Elliott, a doctoral student in the laboratory of Ahmad Hariri, PhD.
Researchers have long believed that some biological aspects indicating risk for psychiatric disorders were specific to particular disorders. By studying specific groups of patients, such as those with schizophrenia only, researchers may have mistaken general risk factors for specific risk factors.
Current research suggests that a person’s risk for developing mental illness is not specific to one form of disorder, however, but is instead shared across many different disorders.
“In other words, there may be a single risk factor that predicts whether an individual develops any form of psychiatric disorder, be it depression, post-traumatic stress disorder, addiction, or even schizophrenia,” said Elliott.
For the study, the researchers evaluated 605 university students who were enrolled in the larger Duke Neurogenetics Study. Many of the participants met criteria for psychiatric disorders, including alcohol or substance use disorder, major depressive disorder, and bipolar disorder.
Rather than dividing the participants into groups based on their specific diagnosis, Elliott and colleagues gave each person a score that reflected their general mental health burden based on psychiatric evaluations. The researchers found that the abnormality was present in participants who had a higher risk for mental illness.
Using functional magnetic resonance imaging (fMRI) of the whole brain, the researchers identified a link between the individual scores and increased connectivity between the visual cortex and specific brain networks important for high level thinking.
The networks — known as the default mode network and the frontoparietal network — are critical for behaviors aimed at completing a particular task and for suppressing internal distractions to filter sensory information relevant to that task.
The findings are published in the journal Biological Psychiatry.