For the 2.2 million American adults with obsessive-compulsive disorder, the need to perform routines and rituals over and over cause distress, getting in the way of everyday life. Now, researchers from the University of Cambridge in the UK say compulsions from the disorder may derive from misfiring of the brain’s control system.
They publish their results in the American Journal of Psychiatry.
According to the National Institutes of Mental Health (NIMH), individuals with obsessive-compulsive disorder (OCD) have frequent upsetting thoughts that they try to control by repeating certain rituals or behaviors.
Though healthy people also have rituals – including checking to see that the stove is off before leaving the house – people with OCD obsessively perform their rituals, even though they interfere with daily life.
“While some habits can make our life easier, like automating the act of preparing your morning coffee, others go too far and can take control of our lives in a much more insidious way, shaping our preferences, beliefs, and in the case of OCD, even our fears,” notes Prof. Trevor Robbins, a study author from the Department of Psychology at Cambridge.
He and Dr. Claire Gillan led a team of researchers to investigate the idea that compulsions in OCD result from an “overactive habit-system.”
To do so, they scanned 37 OCD patients’ brains and those of 33 healthy controls who did not have the disorder as they all performed a pedal-pressing behavioral activity to avoid mild electric shocks to the wrist.
Previous research has established that the caudate nucleus – a brain region that must fire correctly for us to be in control of our habits – is overactive when OCD symptoms are incited in patients.
- OCD sometimes runs in families
- The disorder affects men and women equally and usually appears in childhood or early adulthood
- One third of adults with OCD develop symptoms as children.
In their latest study, the researchers observed that patients with OCD were not as able to stop the pedal-pressing habits as the controls were, and this was linked to overactive brain activity in the caudate.
The team says their finding that the OCD patients’ habits prompted overactivity in the caudate adds evidence to the idea that OCD compulsions could be caused by the habit system in the brain.
But these findings are not simply OCD-specific; they may extend to other areas of psychiatry. “It’s not just OCD; there are a range of human behaviors that are now considered examples of compulsivity, including drug and alcohol abuse and binge-eating,” says Dr. Gillan.
She explains that all of these behaviors involve the “loss of top-down control,” likely stemming from miscommunication between habit-controlling brain regions and those that control voluntary behavior – such as the prefrontal cortex. “As compulsive behaviors become more ingrained over time, our intentions play less and less of a role in what we actually do,” she says.
Prof. Robbins adds that conditions such as OCD and other compulsive disorders “are among the most difficult to treat, whether by cognitive behavior therapy or by drugs.”
Prof. Barbara Sahakian, another study author, concludes:
”This study emphasizes the importance of treating OCD early and effectively before the dysfunctional behavior becomes entrenched and difficult to treat. We will now focus on the implications of our work for future therapeutic strategies for these compulsive disorders.”
In September 2014, Medical News Today reported on a new clinical guideline that recommended deep brain stimulation for cases of OCD that do not respond to medication.