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Obsessive compulsive disorder: Overview


What is obsessive compulsive disorder (OCD)?

OCD occurs when a person suffers from troubling and intrusive thoughts or images in their head and/or follows repetitive or strict patterns of behaviour (rituals) to feel less worried.

Most people with OCD, except very young children, recognize that the thoughts and/or images they experience are not true. However, they still believe them and feel compelled, or forced, to perform certain rituals to make them less troubling. This link between thoughts and behaviour means that it is more common for someone with OCD to experience obsessions and compulsions together than to experience either an obsession or a compulsion on its own.

Often, people with OCD engage in compulsive behaviour out of fear that something terrible will happen if they do not follow certain patterns. Completing the behaviour helps them feel “just right”, if only for a short time. Teens and adults can express their worries about what will happen if they do not perform their ritual, but children – especially very young children – cannot do so.

Where does a child usually display their OCD symptoms?

Children and teens are more likely to display symptoms of OCD, at least in the early stages, in the safety of their own home. However, in the more severe stages of the disorder, OCD can often affect other parts of their lives, including their schooling.

What causes OCD?

The exact cause of OCD is unknown, but research is looking at many different factors.

  • Genetics (characteristics that run in families) are known to play an important role in OCD. People who have relatives with OCD or anxiety have a greater chance of developing OCD in childhood.
  • Abnormal levels of neurotransmitters (brain chemicals that carry information) are also known to play a part. In particular, low or imbalanced serotonin can contribute to OCD.
  • OCD can also occur after a streptococcal infection. However, this type of OCD results from an autoimmune reaction where the body confuses its own tissues for the strep infection. Symptoms occur suddenly (many parents describe as almost overnight). As a result, it is very different from what occurs in what is normally considered to be childhood OCD.

How common is OCD?

OCD affects between 1 and 4 per cent of children and teens, making it the fourth most common youth mental health problem today. Some studies have shown that as many as 8 per cent of children and teens may have a mild form of OCD. This means that, while they may have some symptoms, they do not interfere significantly with their everyday routine.

Does OCD occur with other mental health conditions?

It is not unusual for a child or teen with OCD to have another mental health condition, such as:

Some of these mental health conditions can be treated alongside OCD, but others may need other treatments. For example, tic disorders respond to a therapy called Comprehensive Behavioural Intervention for Tics (CBIT). During CBIT therapy, a person learns to recognize the urge that arises before the tic and then learns a competing response to essentially block the tic. Another type of anxiety disorder, such as social anxiety or generalized anxiety, usually responds well to cognitive behavioural therapy (CBT). This involves understanding the relationship between thoughts, feelings and behaviours and learning coping strategies to manage distressing thoughts.

What to do if you suspect your child has OCD

If you suspect your child has OCD, speak to your child's doctor. They can refer your child to a specialist for diagnosis and treatment.

If your child has already been diagnosed with anxiety, seek help for OCD from someone who is experienced in using CBT and treating OCD. It is not enough to see a therapist experienced in anxiety treatment on its own, as different skills are needed to treat OCD.

Key points

  • OCD is a disorder that causes a person to experience intrusive thoughts and/or repetitive behaviour.
  • The main causes of OCD include genetics and chemical imbalances.
  • A child may have OCD on its own or with other mental health conditions such as an anxiety disorder, depression, ADHD or an eating disorder.
  • Speak to your child’s doctor or paediatrician if you suspect that your child has OCD.

Further information

For more information about OCD, please see the following pages:

OCD: Signs and symptoms

OCD: How it affects your child's life

OCD: Treatment with psychotherapy and medications

OCD: How to help your child​

Sandra L. Mendlowitz, PhD, C Psych​​



The following books and websites have some useful advice about OCD for parents and teens.


Chansky, T. (2001). Freeing Your Child from Obsessive-Compulsive Disorder: a Powerful, Practical Program for Parents of Children and Adolescents​. Harmony.

Derisley, J., et al (2008). Breaking Free from OCD: a CBT Guide for Young People and Their Families. London: Jessica Kingsley Publishers. 

Dotson, A. (2014). Being Me with OCD: How I Learned to Obsess Less and Enjoy My Life. Free Spirit Publishing.  

Jassi, A. (2013). Can I Tell You about OCD? A Guide for Friends, Family, and Professionals. London: Jessica Kingsley Publishers.


International OCD Foundation (2016). OCD in Kids (2016). Obsessive Compulsive Disorder

AnxietyBC (2016). Obsessive Compulsive Disorder​​​​