Imaging may show biology of disorders
Research could allow diagnosis of autism, ADHD and OCD using brain scans
Imagine if we could use data from a brain image to diagnose autism or ADHD. Or if we could use that same image to predict the right treatment.
Right now, we diagnose autism spectrum disorder (ASD), attentiondeficit/ hyperactivity disorder (ADHD) or obsessive compulsive disorder (OCD) based on information about a person’s experiences and behaviours that fit a textbook definition.
For the roughly 15 per cent of children in Ontario who have at least one of these disorders, there are no blood tests or brain scans to help make a diagnosis. In fact, some of the clinical symptoms that define one disorder can often be part of the picture of another.
For example, symptoms of inattention, hyperactivity and impulsivity underlie a diagnosis of ADHD, but these symptoms are often present in children presenting with symptoms of ASD or OCD.
This overlap between children with ASD, ADHD and OCD raises an important question: What are the biological differences and similarities between different neurodevelopmental disorders? If we can answer that question, would we then be able to provide diagnoses that are based on biology? And would that then ac- celerate treatment discovery?
I’m part of a research team trying to answer these questions. Recently, we published the first research using advanced scanning to study the brain’s “white matter” across all three disorders. Previous brain imaging studies have examined these disorders separately.
White matter is essentially the wiring that connects different parts of the brain. It is essential for the fast transfer of messages between distant brain regions. Healthy white matter is critical for complex brain functioning, such as managing social interactions and regulating attention and behaviour.
We discovered in our study of 200 children that some changes in the wiring of the brain looked similar in children with autism, ADHD and OCD, compared to children without a disorder. If there are similar brain changes present in all three disorders, it raises the possibility that treatments that work for one disorder may work for others as well.
We also found that more miswiring was related to greater challenges in everyday functioning, regardless of diagnosis. This provides hope that we may be able to develop treatments appropriate for children with ASD, ADHD or OCD that improve everyday functioning, and potentially improve related brain wiring.
By looking across different disor- ders and focusing on symptoms that are common across disorders (like impaired everyday functioning), our study suggests that we are moving closer to understanding the underlying biology of these disorders.
In the future, these advances will allow us to move away from diagnoses based on textbook definitions and move toward making diagnoses based on biological markers.
We hope that this type of advanced imaging along with other measures will help us reclassify these disorders in a way that more closely represents their underlying biology. We think that this will make the job of discovering new treatments much easier.
For complex disorders such as autism, ADHD and OCD, treatments that make a difference early in life may change the way a child develops. So the earlier and more precisely we can diagnose and treat these disorders, the better the chances for good long-term outcomes. Dr. Stephanie Ameis is a physicianscientist in the Campbell Family Mental Health Research Institute, the McCain Centre for Child, Youth and Family Mental Health at CAMH and the Child and Youth Mental Health Collaborative at CAMH, Sick Kids and the University of Toronto. She is a member of the Province of Ontario’s Neurodevelopmental Disorders (POND) Network and worked with POND lead Dr. Evdokia Anagnostou on the recently published brain imaging study. Doctors’ Notes is a weekly column by members of the U of T Faculty of Medicine. Email doctorsnotes@thestar.ca.