They clean their hands, many times in a row. They flip switches on and off, over and over. They check — and re-check, then check again — that they’ve turned the stove off.
No one knows exactly what drives people with
They clean their hands, many times in a row. They flip switches on and off, over and over. They check — and re-check, then check again — that they’ve turned the stove off.
No one knows exactly what drives people with obsessive-compulsive disorder to do what they do, even when they’re fully aware that they shouldn’t do it, and when it interferes with their ability to live a normal life.
This lack of scientific understanding has a serious consequence — experts say approximately half of all sufferers lack effective treatment options.
But new research could help guide future treatment to help more of them. In a study released Thursday, researchers were able to pinpoint the specific brain areas and processes linked to the repetitive behaviors common to patients with OCD. Larger than any previous study, researchers studied brain scans from hundreds of people with OCD, as well as the scans of people who did not have the condition.
Put simply, the study suggests that the brains of OCD patients get stuck in a loop of “wrongness” that prevents sufferers from stopping behaviors even if they know they should.
Errors and stop signals
Researchers from Michigan Medicine gathered together the largest-ever pool of task-based functional brain scans and other data from OCD studies around the world, and combined them for a new meta-analysis published in Biological Psychiatry.
“These results show that, in OCD, the brain responds too much to errors, and too little to stop signals, abnormalities that researchers had suspected to play a crucial role in OCD, but that had not been conclusively shown due to small numbers of participants in the individual studies,” says Luke Norman, Ph.D., lead author of the new study and a postdoctoral research fellow in the U-M Department of Psychiatry.
“By combining data from 10 studies, and nearly 500 patients and healthy volunteers, we could see how brain circuits long hypothesized to be crucial to OCD are indeed involved in the disorder,” he says. “This shows the power of doing this kind of research more collaboratively.”
New targets for therapy
Norman works with U-M psychiatry faculty members Kate Fitzgerald, M.D., M.S., and Stephan Taylor, M.D. Fitzgerald co-directs the Pediatric Anxiety Disorders Program at Michigan Medicine, U-M’s academic medical center, and leads a clinical trial that is currently seeking teens and adults with OCD to test the ability of targeted therapy sessions to treat OCD symptoms.
“This analysis sets the stage for therapy targets in OCD, because it shows that error processing and inhibitory control are both important processes that are altered in people with the condition,” says Fitzgerald.
“We know that patients often have insight into their behaviors, and can detect that they’re doing something that doesn’t need to be done,” she adds. “But these results show that the error signal probably isn’t reaching the brain network that needs to be engaged in order for them to stop doing it.”
Zeroing in on brain differences
In their paper, the U-M researchers focused on the cingulo-opercular network — a collection of brain areas linked by highways of nerve connections deep in the center of the brain. The area normally acts as a monitor for errors or the potential need to stop an action, and gets the decision-making areas at the front of the brain involved when it senses something is “off.”
The pooled brain scan data used in the new paper was collected when OCD patients and healthy people were asked to perform certain tasks while lying in a powerful functional MRI scanner. In all, the new analysis included scans and data from 484 children and adults, both medicated and not.
Norman led th