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An individual with obsessive-compulsive disorder (OCD) is overcome with an urge to engage in unproductive habits, such as excessive hand washing or lock checking. Though recognizing these behaviors as irrational, the person remains trapped in a cycle of life-disrupting compulsions. Previous studies found that OCD patients have abnormalities in two different brain systems—one that creates habits and one that plays a supervisory role. Yet whether the anomalies drive habit formation or are instead a consequence of doing an action over and over remained unclear.
To resolve this question, a team at the University of Cambridge monitored brain activity while people were actually forming new habits. Lapses in supervision are to blame, the researchers reported in a study published online in December 2014 in the American Journal of Psychiatry. They scanned 37 people with OCD and 33 healthy control subjects while they learned to avoid a mild shock by pressing on a foot pedal. Pressing the pedal became a habit for everyone, but people with OCD continued to press even when the threat of shock was over. Those with OCD showed abnormal activity in the supervisory regions important for goal-directed behavior but not in those responsible for habit formation.
The finding suggests that shoring up the goal-directed systems through cognitive training might help people with OCD. The growing understanding of OCD's roots in the brain may also help convince individuals to engage in standard habit-breaking treatments, which expose a person to a trigger but prevent his or her typical response. “It's hard for people to not perform an action that their whole body is telling them to do,” says first author Claire Gillan, now at New York University. “So if you have an awareness that the habit is just a biological slip, then it makes OCD a lot less scary and something you can eventually control.”