People who live with obsessive-compulsive disorder (OCD) might have new answers regarding their frustrating mental health condition, thanks to a new study.

Despite not being able to pinpoint a specific cause for the disorder, scientists have believed that OCD may be caused by imbalances in neurotransmitters in the brain, such as serotonin. It might also be caused by gene mutations. But the new study, published in the American Journal of Psychiatry, suggests that OCD could possibly be linked to an overactive habit system in the brain.

OCD is characterized by having a recurring obsession, something a person can't let go of in their mind. This could include obsessions about contamination — washing hands continuously — or even losing control, such as the fear of developing an urge to commit self-harm or harm someone else. OCD can also involve obsessions about perfectionism, unwanted sexual thoughts, or the fear of offending God in some way and being punished for it. The second part of OCD is the compulsive aspect, where the person acts on their obsessions by doing a compulsive ritual as a way to rid themselves of this worry. For example, some people will repeat body motions, such as taking steps or tapping things, as a way to reach a “safe” or “right” number that will avoid them from experiencing catastrophe.

Losing Control Of Habits

In the new study, the researchers scanned the brains of 37 patients who had OCD, as well as the brains of 33 healthy participants without the disorder. While scanning their brains, the researchers had them perform a simple pedal-pressing behavioral response, which they did to avoid getting a mild electric shock to their wrists. The patients with OCD were less able to stop their pedal-pressing impulses, and showed excessive brain activity in the caudate nucleus, a region of the brain that controls habits.

“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,” said Dr. Claire Gillian, a lead author of the study who is now at New York University, in the press release. “What all these behaviors 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 behavior. As compulsive behaviors become more ingrained over time, our intentions play less and less of a role in what we actually do.”

In other words, people who suffer from OCD no longer have control over their habits, even if they know, rationally, that they’re unnecessary and harmful to their mental health.

According to the International OCD Foundation, OCD can only be diagnosed by a trained therapist, who looks for three signs: the person has obsessions, repeatedly follows through on compulsive habits, and finds that a lot of time gets taken away by these compulsions. Basically, the OCD gets in the way of their daily functioning. When it gets to a severe point, it’s important for people with OCD to understand what’s causing their worries and obsessions in order to help them get to the root faster, and halt their compulsions with practice and therapy.

“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,” said Professor Trevor Robbins, another author of the study, in the press release. “Such conditions — where maladaptive, repetitive habits dominate our behavior — are among the most difficult to treat, whether by cognitive behavior therapy or by drugs.”

Source: Gillan C, Fineberg N, Robbins T, et al. Functional Neuroimaging of Avoidance Habits in Obsessive-Compulsive Disorder. The American Journal of Psychiatry. 2014.