Causes of OCD

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The origin of OCD lies in the brain. The brain of people with OCD functions differently, in other words, it makes them repeat certain behaviours several times when faced with normal situations which the brain perceives as being dangerous. In fact, it is unknown what causes this abnormal brain function. It is likely that there is no single cause of OCD, but rather there are several causes that may lead to a person developing the disorder.

In terms of mental disorders, matters relating to the cause are more complicated than in physical diseases and, currently, we do not know the origins behind any mental disorders. Rather than talking about causes, it is more helpful to discuss vulnerabilities and risk factors.

Risk factors

DNA molecule or helix

Genetics. When someone has OCD, their relatives (including their descendants) are also more likely to develop OCD, as genetic factors mean that relatives are more susceptible to the disorder. However, this does not necessarily mean that if a person has OCD, their descendants will definitely develop it. We do not currently know which genes are involved in OCD.

Person with symbols on the head representing stress, anxiety, confusion, disorientation, headache or migraine

Stress or traumatic situations. Stress or trauma can cause the symptoms of OCD. This does not imply that OCD is caused by stress, but rather that stress can act as a trigger of OCD or prolong the symptoms once the disorder has developed.

Patient with swollen glands

Infections. A subgroup of child and adolescent patients has been described in which they develop sudden‑onset OCD after having suffered an infection (primarily tonsillitis) which can trigger an autoimmune process and provoke obsessive‑compulsive symptoms.

Substantiated information by:

Luisa Lázaro García
Miquel Àngel Fullana Rivas

Published: 7 February 2019
Updated: 7 February 2019

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