The Different Causes of Developing OCD

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Mental illnesses such as obsessive-compulsive disorder (OCD) are often chalked up to “chemical imbalances." In reality, the situation is much more complex. No one knows exactly what causes OCD, though there are certainly specific risk factors that seem to be present, such as brain abnormalities, chemical changes, genetics, and environment. 

Is OCD Caused by a Chemical Imbalance?

Changes in the neurochemical serotonin, as well as in the neurochemicals dopamine and glutamate, are likely present in OCD. Indeed, medications like the antidepressants known as selective serotonin reuptake inhibitors (SSRIs) improve symptoms for many people.

In addition, research in animals and humans seems to suggest that changes in various neurochemicals are at least partly responsible for OCD symptoms. However, it is not always clear to what degree these neurochemical changes cause OCD symptoms or whether they come about as the result of experiencing OCD symptoms.

Also, recent studies have shown that OCD very likely involves functional changes in the actual structure of the brain in combination with changes in neurochemicals, rather than simple chemical imbalances.

New neuroimaging research has shown that in people with OCD, specific areas of the brain actually function differently than the same areas in those without OCD. However, this finding still doesn't fully explain how the difference in brain function contributes to the development of OCD.​

So, while neurochemicals are certainly important for understanding and treating OCD, they are definitely not the whole picture.

Genetics and Environment Play a Large Role

Whether or not someone in your family has OCD is one of the biggest risk factors for developing OCD. The closer the family member and the younger they were when symptoms started, the higher your risk, though no specific gene has been pinpointed yet.

In addition, the environment we live in can have a huge influence on whether OCD symptoms will develop. Someone with a very strong biological vulnerability to OCD may never go on to develop the illness unless they experience the "right" environmental conditions, such as chronic stress (especially early in life) or a traumatic loss.

The Role of Behavior

Behavior may also play a role in the development of OCD, particularly when under stress. Your brain starts to associate certain objects or situations with fear and in response, you may start avoiding them or creating rituals to lessen the anxiety you feel when you encounter them.

For example, you may have had no problem shaking hands with strangers, but while under a lot of stress, you suddenly began to associate shaking hands with strangers with getting sick or spreading germs. You may then stop engaging in this normal act of politeness or get out your hand sanitizer immediately after shaking someone's hand if you can't avoid it.

Because your behavior reinforces your fear, being afraid of catching a sickness or someone else's germs could then begin to spread to touching anything that others have touched. This could lead to washing your hands multiple times a day until they're raw and chapped.


The best and most effective treatments for most OCD sufferers are psychotherapy and/or medication, such as SSRIs. Many people with OCD can live fulfilling, productive lives by learning coping strategies and sticking to their treatment plans. If you think you may have OCD, be sure to talk to your physician.

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Owen Kelly, PhD
Owen Kelly, PhD, is a clinical psychologist, professor, and author in Ontario, ON, who specializes in anxiety and mood disorders.