Obsession, compulsion and the misfiring mind

brainspagThe compulsions and rituals typical of Obsessive Compulsive Disorder (OCD) are the result of misfiring within the brain and not by excessive worry or distorted beliefs, according to the results of a new study by the University of Cambridge.

The latest research challenges what has been previously understood of OCD, pointing away from emotional disorder and instead to an overactive habit system.


In the study, 70 participants; half of those diagnosed with OCD and half with no history of OCD, had their brains scanned for activity during the performance of repetitive tasks. 

The experiment involved pressing a pedal to avoid a small electric shock. Patients with OCD were less able to stop pressing the pedal to avoid the shock.

Brain scans show that this behaviour was linked to excessive brain activity in the caudate nucleus, a part of the brain responsible for controlling habitual behaviour.


The findings may be far more reaching than helping those with Obsessive Compulsive Disorder. The new understanding of the brain could help develop new treatments for those with a range of damaging compulsive behaviours, such as drug abuse, alcohol abuse and binge-eating. Dr Gillan comments on the common factor of compulsions having ‘loss of top-down control’;

“What all these behaviours have in common is the loss of top-down control, perhaps due to miscommunication between regions that control our habit and those such as the prefrontal cortex that normally help control volitional behaviour. As compulsive behaviours become more ingrained over time, our intentions play less and less of a role in what we actually do.”


Cambridge Behavioural and Clinical Neuroscience Institute investigating the possibility that compulsions in OCD are products of an overactive habit-system

creative commons licensed (BY-NC-SA) flickr photo by Mukumbura