Obsessive-compulsive disorder is often overused by self-identified “neat freaks” and “germaphobes.” OCD is more than just an affinity for tidiness or an aversion to germs; it’s a disorder in which a person struggles to control their own compulsions. Even when they consciously know that there is no reason for them to engage in a certain behavior, their brains won’t allow them to stop a compulsive activity.
For many psychological disorders, it’s difficult to pinpoint their exact cause and the parts of the brain where the problem lies. However, through studies, researchers have examined which parts of the brain are most active in people with OCD and how they work in the wider context of the brain. Through research, scientists have identified several parts of the brain that are likely to be affected by obsessive-compulsive disorder, including the following:
The orbital cortex is a region of the brain in the prefrontal lobe that’s responsible for a variety of cognitive processes related to decision making. Decision making involves multiple factors, including response inhibition, inferred value, emotional processing, and social behavior. However, the function of the orbital cortex that’s relevant to OCD is mistake detection. If you perform a task, your orbital cortex lights up to let you know it went well, or you made a mistake.
Performing a task correctly can make you feel good and accomplished while performing a task incorrectly causes stress and negative feelings. This is how your brain motivates you to get better, to grow skills, and to avoid costly mistakes. You’ve probably experienced this brain function many times in your life. Think back to when you were in school, and you answered a question in front of the whole class. Answering correctly felt good, but a wrong answer caused your heart to drop.
Scientists studied the effects of correctly and incorrectly performed tasks on the orbital cortex of rhesus monkey brains. The monkeys were given a task and were awarded with juice when the task went well and saltwater when it went poorly. They found that the orbital cortex lit up more intensely and for longer when monkeys performed a task incorrectly. In this part of the brain, the intense reaction lets you know something went wrong because of some action or misstep you made.
People with OCD tend to have more intense reactions in the orbital cortex, causing them to feel like something was wrong even when they are performing normal everyday tasks. For instance, washing your hands is something that most people do without thinking. But a person with OCD might wash their hands and have their orbital cortex light up. Even though their conscious mind is aware that they didn’t do anything wrong, their brain is telling them that they made a mistake and need to start over.
The next part of the brain that’s affected by OCD is the cingulate gyrus, and it works hand in hand with the orbital cortex. This part of your brain deals with motivation and behavioral responses. It receives inputs from the limbic system, which is tied to reward and learning. Actions lead to positive or negative responses, which are linked in the brain by the cingulate gyrus. For that reason, this part of the brain has a strong influence on your behavior when it comes to emotional responses, reward, and learning. It’s also connected to the orbital cortex by linking an emotional response to the signal that you did something wrong. If your orbital cortex tells you that you made a mistake, your cingulate gyrus causes you to feel discomfort or anxiety until you fix that mistake.
People with OCD will also experience more intense activity in this part of the brain. Using the handwashing example, a person with OCD may wash their hands and have their orbital cortex tell them they did something wrong. Unfortunately, they often can’t just say, “oh well,” and then walk away. Their cingulate gyrus will make them feel uneasy until the problem is solved, even when they know that nothing’s wrong. For this reason, they may try to wash their hands multiple times in order to satisfy feelings of anxiety.
The final key part of the brain that’s related to OCD is the caudate nucleus. This part of the brain is responsible for procedural learning, associative learning, and inhibitory control of actions. This last function is the key to changing gears when we have impulses or anxieties that are out of our control. The caudate nucleus gives us the control to override compulsions and intrusive thoughts. For instance, if you arrive at work and start to wonder if you locked the door when you left, you are faced with the choice to go home and check or just forget about it and hope you locked it. If your home is far away, you might recognize that it’s unrealistic to return home, and your caudate nucleus will allow you to move on with your day and forget about it.
People with OCD often have less activity in their caudate nucleus. So while their orbital cortex and cingulate gyrus work overtime to trigger anxiety in response to a perceived mistake, the caudate nucleus is unable to help them overcome their compulsions to repeatedly try to fix the mistake.
Researcher and psychiatrist Dr. Jeffery Schwartz calls the phenomenon where these parts of the brain cause nearly irresistible compulsions “brain lock.” But he also says that there is a way to overcome brain lock by manually overcoming compulsions. In a 1998 review, Schwartz said that cognitive-behavioral therapy could help to “modify cerebral metabolic activity” in a way that can help people with OCD train their brains to better regulate compulsions. Cognitive-behavioral therapy is a common psychotherapy that’s used in a variety of treatment settings. It involves identifying triggers and coming up with coping mechanisms to help modify behavior.
If you or someone you know is struggling with obsessive-compulsive disorder, there is help available. Learn more about OCD and how it can be effectively treated to take your first steps toward better mental health today.
Bailey, R. (2019, July 12). What Is the Cingulate Gyrus? Retrieved from https://www.thoughtco.com/cingulate-gyrus-and-the-limbic-system-4078935
Healthline. (2015, April 14). Caudate Nucleus Function, Anatomy & Definition | Body Maps. Retrieved from https://www.healthline.com/human-body-maps/caudate-nucleus
Schwartz, J. M. (2018, August 6). Neuroanatomical aspects of cognitive-behavioural therapy response in obsessive-compulsive disorder: The British Journal of Psychiatry. Retrieved from https://www.cambridge.org/core/journals/the-british-journal-of-psychiatry/article/neuroanatomical-aspects-of-cognitivebehavioural-therapy-response-in-obsessivecompulsive-disorder/07EAB6C55442B1197CB935D7DF517293
Torregrossa, M. M., Quinn, J. J., & Taylor, J. R. (2008, February 1). Impulsivity, compulsivity, and habit: the role of orbitofrontal cortex revisited. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2265211/
Tsujimoto, S., Genovesio, A., & Wise, S. P. (2009, February 25). Monkey Orbitofrontal Cortex Encodes Response Choices Near Feedback Time. Retrieved from https://www.jneurosci.org/content/29/8/2569