LONDON, ON - Psychiatric disorders are often difficult to diagnose. As research advances, we are learning there are multiple subtypes of illness that differ in symptoms and treatment needs, making classification even harder. Post-traumatic stress disorder (PTSD) is one example. Individuals with the more common type of PTSD experience active defensive responses like hyperarousal or outbursts of emotion while those with the dissociative subtype experience additional passive defensive responses like ‘shutting down’ or out-of-body experiences.
In a new study from Lawson Health Research Institute and Western University, researchers combined brain imaging and machine learning to classify with 92 per cent accuracy whether individuals had PTSD and whether or not it was the dissociative subtype. The results highlight the promise of brain imaging as a tool for early diagnosis of psychiatric illness, helping to predict symptom development and treatment needs.
The study involved 181 research participants, including those diagnosed with the more common form of PTSD, the dissociative subtype of PTSD, and healthy individuals with no history of PTSD. They participated in functional magnetic resonance imaging (fMRI) at St. Joseph’s Health Care London and Robarts Research Institute.
Researchers used the high-powered imaging to analyze patterns of resting-state brain activity where participants simply remained in a state of restful wakefulness in an fMRI scanner. The team found that unique patterns of brain activity differed significantly between the three groups.
“Our research group has been leading a number of studies that have shown differences in brain activity and neural connections between healthy individuals and those with different subtypes of PTSD,” says Dr. Ruth Lanius, a researcher at Lawson, professor at Schulich School of Medicine & Dentistry at Western University and psychiatrist at London Health Sciences Centre. “This study further validates that unique patterns of brain activity are associated with different forms of PTSD.”
In the second part of the study, the research team inputted the patterns of brain activity into a machine learning computer algorithm. They found the machine learning system could analyze brain scans to predict whether an individual had PTSD, the dissociative subtype of PTSD or no PTSD with 92 per cent accuracy.
“Our study suggests brain activity can be used to assist diagnosis of psychiatric disorders and help predict symptoms,” says Andrew Nicholson, PhD, lead author on the study and a post-doctoral fellow at Schulich Medicine & Dentistry who is conducting research at Lawson. “Patterns of brain activity are objective biomarkers that could be used to diagnose PTSD and, with more research, even predict response to treatment.”
Objective biomarkers hold promise for transforming psychiatric medicine. “The field of psychiatry does not currently have objective biomarkers like those used to diagnose and understand other illnesses or diseases like cancer,” says Nicholson. “By discovering and validating patterns of brain activity as biomarkers, we can bring objective measures to psychiatry and transform patient care.”
The study, “Machine learning multivariate pattern analysis predicts classification of posttraumatic stress disorder and its dissociative subtype: A multimodal neuroimaging approach,” is published in Psychological Medicine.
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Lawson Health Research Institute is one of Canada’s top hospital-based research institutes, tackling the most pressing challenges in health care. As the research institute of London Health Sciences Centre and St. Joseph’s Health Care London, our innovation happens where care is delivered. Lawson research teams are at the leading-edge of science with the goal of improving health and the delivery of care for patients. Working in partnership with Western University, our researchers are encouraged to pursue their curiosity, collaborate often and share their discoveries widely. Research conducted through Lawson makes a difference in the lives of patients, families and communities around the world. To learn more, visit www.lawsonresearch.ca.
The Schulich School of Medicine & Dentistry at Western University is one of Canada’s preeminent medical and dental schools. Established in 1881, it was one of the founding schools of Western University and is known for being the birthplace of family medicine in Canada. For more than 130 years, the School has demonstrated a commitment to academic excellence and a passion for scientific discovery.
Western delivers an academic experience second to none. Since 1878, The Western Experience has combined academic excellence with life-long opportunities for intellectual, social and cultural growth in order to better serve our communities. Our research excellence expands knowledge and drives discovery with real-world application. Western attracts individuals with a broad worldview, seeking to study, influence and lead in the international community.
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