Twin and family studies have shown that people with first-degree relatives (such as a parent, sibling, or child) who have OCD are at a higher risk for developing OCD themselves. The risk is higher if the first-degree relative developed OCD as a child or teen.
Ongoing research continues to explore the connection between genetics and OCD and may help improve OCD diagnosis and treatment.
Brain Structure and Functioning
Brain imaging techniques have allowed researchers to study the activity of specific areas of the brain, leading to the discovery that some parts of the brain are different in people with OCD when compared to those without. Despite this finding, it is not known exactly how these differences relate to the development of OCD. Imbalances in the brain chemicals serotonin and glutamate may play a part in OCD.
People who have experienced abuse (physical or sexual) in childhood or other trauma are at an increased risk for developing OCD.
The behavioral theory suggests that people with OCD associate certain objects or situations with fear. They learn to avoid those things or learn to perform ‘rituals’ to help reduce the fear. This fear and avoidance or ritual cycle may begin during a period of intense stress, such as when starting a new job or just after an important relationship comes to an end.
Once the connection between an object and the feeling of fear becomes established, people with OCD begin to avoid that object and the fear it generates, rather than confronting or tolerating the fear.
Most people have unwelcome or intrusive thoughts at certain times, but for individuals with OCD, the importance of those thoughts are exaggerated.