Machine learning links dimensions of mental illness to abnormalities of brain networks

August 2, 2018, Perelman School of Medicine at the University of Pennsylvania
Cross clinical diagnostic categories. Credit: Penn Medicine

A new study using machine learning has identified brain-based dimensions of mental health disorders, an advance towards much-needed biomarkers to more accurately diagnose and treat patients. A team at Penn Medicine led by Theodore D. Satterthwaite, MD, an assistant professor in the department of Psychiatry, mapped abnormalities in brain networks to four dimensions of psychopathology: mood, psychosis, fear, and disruptive externalizing behavior. The research is published in Nature Communications this week.

Currently, psychiatry relies on patient reporting and physician observations alone for clinical decision making, while other branches of medicine have incorporated biomarkers to aid in diagnosis, determination of prognosis, and selection of treatment for patients. While previous studies using standard clinical diagnostic categories have found evidence for , the high level of diversity within disorders and comorbidity between disorders has limited how this kind of research may lead to improvements in clinical care.

"Psychiatry is behind the rest of medicine when it comes to diagnosing illness," said Satterthwaite. "For example, when a patient comes in to see a doctor with most problems, in addition to talking to the patient, the physician will recommend lab tests and imaging studies to help diagnose their condition. Right now, that is not how things work in psychiatry. In most cases, all psychiatric diagnoses rely on just talking to the patient. One of the reasons for this is that we don't understand how abnormalities in the brain lead to . This research effort aims to link issues and their associated brain network abnormalities to psychiatric symptoms using a data-driven approach."

To uncover the associated with , the team studied a large sample of adolescents and young adults (999 participants, ages 8 to 22). All participants completed both functional MRI scans and a comprehensive evaluation of psychiatric symptoms as part of the Philadelphia Neurodevelopmental Cohort (PNC), an effort lead by Raquel E. Gur, MD, Ph.D., professor of Psychiatry, Neurology, and Radiology, that was funded by the National Institute of Mental Health. The brain and data were then jointly analyzed using a machine learning method called sparse canonical correlation analysis.

This analysis revealed patterns of changes in brain networks that were strongly related to psychiatric symptoms. In particular, the findings highlighted four distinct dimensions of psychopathology—mood, psychosis, fear, and disruptive behavior—all of which were associated with a distinct pattern of abnormal connectivity across the brain.

The researchers found that each brain-guided contained symptoms from several different clinical diagnostic categories. For example, the mood dimension was comprised of symptoms from three categories, e.g. depression (feeling sad), mania (irritability), and obsessive-compulsive disorder (recurrent thoughts of self-harm). Similarly, the disruptive externalizing behavior dimension was driven primarily by symptoms of both Attention Deficit Hyperactivity Disorder(ADHD) and Oppositional Defiant Disorder (ODD), but also included the irritability item from the depression domain. These findings suggest that when both brain and symptomatic data are taken into consideration, psychiatric symptoms do not neatly fall into established categories. Instead, groups of symptoms emerge from diverse clinical domains to form dimensions that are linked to specific patterns of abnormal connectivity in the brain.

"In addition to these specific brain patterns in each dimension, we also found common brain connectivity abnormalities that are shared across dimensions," said Cedric Xia, a MD-Ph.D. candidate and the paper's lead author. "Specifically, a pair of brain networks called default mode network and frontal-parietal network, whose connections usually grow apart during brain development, become abnormally integrated in all dimensions."

These two brain networks have long intrigued psychiatrists and neuroscientists because of their crucial role in complex mental processes such as self-control, memory, and social interactions. The findings in this study support the theory that many types of psychiatric illness are related to abnormalities of .

The team also examined how psychopathology differed across age and sex. They found that patterns associated with both mood and psychosis became significantly more prominent with age. Additionally, brain connectivity patterns linked to mood and fear were both stronger in female participants than males.

"This study shows that we can start to use the to guide our understanding of psychiatric disorders in a way that's fundamentally different than grouping symptoms into clinical diagnostic categories. By moving away from clinical labels developed decades ago, perhaps we can let the biology speak for itself," said Satterthwaite. "Our ultimate hope is that understanding the biology of mental illnesses will allow us to develop better treatments for our patients."

Explore further: Pathways in the young brain are associated with susceptibility for mental disorders

More information: Cedric Huchuan Xia et al, Linked dimensions of psychopathology and connectivity in functional brain networks, Nature Communications (2018). DOI: 10.1038/s41467-018-05317-y

Related Stories

Pathways in the young brain are associated with susceptibility for mental disorders

April 18, 2018
Adolescence is a period for individual growth and opportunities, but it also coincides with the emergence of many mental disorders. In a study that was recently published in JAMA Psychiatry, Norwegian researchers revealed ...

Breakdown of brain's visual networks linked to mental illness

May 9, 2018
Individual regions of the brain have to team up to get things done. And like in any team, the key to working together is communication.

Specific white matter patterns linked to youth psychopathology

January 29, 2018
(HealthDay)—General psychopathology is a heritable trait in youth that may be detected early in life through brain structural connectivity, according to a study published online Jan. 24 in JAMA Psychiatry.

New method extracts information on psychiatric symptoms from electronic health records

February 26, 2018
Researchers at Massachusetts General Hospital and Harvard Medical School have developed a new method to extract valuable symptom information from doctors' notes, allowing them to capture the complexity of psychiatric disorders ...

Researchers identify brain network organization changes

May 25, 2017
As children age into adolescence and on into young adulthood, they show dramatic improvements in their ability to control impulses, stay organized, and make decisions. Those executive functions of the brain are key factors ...

Study draws links between physical characteristics, like age and body mass index, and brain health

March 7, 2018
March 7, 2018)—Mount Sinai researchers have shown, for the first time, the complex web of links between physical and behavioral characteristics, like age, body mass index (BMI), and substance use, and specific patterns ...

Recommended for you

Self-perception and reality seem to line-up when it comes to judging our own personality

December 14, 2018
When it comes to self-assessment, new U of T research suggests that maybe we do have a pretty good handle on our own personalities after all.

Levels of gene-expression-regulating enzyme altered in brains of people with schizophrenia

December 14, 2018
A study using a PET scan tracer developed at the Martinos Center for Biomedical Imaging at Massachusetts General Hospital (MGH) has identified, for the first time, epigenetic differences between the brains of individuals ...

Researchers discover abundant source for neuronal cells

December 13, 2018
USC researchers seeking a way to study genetic activity associated with psychiatric disorders have discovered an abundant source of human cells—the nose.

Video game players frequently exposed to graphic content may see world differently

December 13, 2018
People who frequently play violent video games are more immune to disturbing images than non-players, a UNSW-led study into the phenomenon of emotion-induced blindness has shown.

New genetic clues to early-onset form of dementia

December 13, 2018
Unlike the more common Alzheimer's disease, frontotemporal dementia tends to afflict young people. It accounts for an estimated 20 percent of all cases of early-onset dementia. Patients with the illness typically begin to ...

How teens deal with stress may affect their blood pressure, immune system

December 13, 2018
Most teens get stressed out by their families from time to time, but whether they bottle those emotions up or put a positive spin on things may affect certain processes in the body, including blood pressure and how immune ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.