There are different theories about why OCD develops. None of these theories can fully explain every person’s experience, but researchers suggest that these are likely to be involved in causing OCD:
Even though we don't fully understand what causes OCD, it can still be successfully treated. You can read more about treatments here.
Some theories suggest that OCD is caused by personal experience. For example:
- If you've had a painful childhood experience, or suffered trauma, abuse or bullying, you might learn to use obsessions and compulsions to cope with anxiety.
- If your parents had similar anxieties and showed similar kinds of compulsive behaviour, you may have learned OCD behaviours as a coping technique.
- Ongoing anxiety or stress, or being part of a stressful event like a car accident or starting a new job, could trigger OCD or make it worse.
- Pregnancy or giving birth can sometimes trigger perinatal OCD. You can read more about perinatal OCD here.
Some research suggests that people with certain personality traits may be more likely to have OCD. For example, if you are a neat, meticulous, methodical person with high standards, you may be more likely to develop OCD.
Some biological theories suggest that a lack of the brain chemical serotonin may have a role in OCD. However, it's unclear this is the cause or is an effect of the condition.
Studies have also looked at genetic factors and how different parts of the brain might be involved in causing OCD, but have found nothing conclusive.
Is childhood OCD caused by an infection?
Some experts have noted that some children seem to develop OCD symptoms very suddenly after having a streptococcal (or strep) infection, such as strep throat or scarlet fever.
However, no one knows why this can happen, and no research has yet been able to identify a physical cause to explain the link. Some children show OCD symptoms for a while and then they fade.
You can read more about the causes of OCD on the OCD-UK website.
This information was published in May 2019. We will revise it in 2022. References are available on request. If you would like to reproduce any of this information see our page on permissions and licensing.