What is obsessive compulsive disorder?

Obsessive compulsive disorder (OCD) is a disabling anxiety disorder. People with OCD experience recurring intrusive thoughts and images, known as obsessions, and perform certain repetitive behaviors, known as compulsions.

OCD is estimated to affect 2-3% of people at some point in their lives. It most commonly develops in late adolescence.


A feeling of tension, nervousness and dread about future events. It can trigger physical symptoms such as a rapid pulse or breathing difficulties.

Causes and risk factors

It is not known exactly what causes OCD. It is thought to develop from a combination of genetic, environmental and biological factors. As with many conditions that affect the mind, it is thought that people with OCD have an imbalance of certain chemicals in the brain that affect mood. People who have a close family member with OCD may be more likely to develop the condition. It is likely that each person's OCD is the result of several interacting factors and is affected by stressful life events, hormone changes and personality traits.

There is no specific test that can be used to diagnose OCD. A doctor can generally diagnose the condition based on a person's thoughts and behaviors.


A chemical substance secreted in one part of an organism and transported to another part of that organism, where it has a specific effect.

Signs and symptoms


An obsession is a recurring and unwanted thought, idea, image or impulse. A person with OCD may find their obsessive thoughts very difficult to dismiss and they may be constantly on their mind. This can be distressing and can lead to considerable anxiety.

Some of the common obsessions that are associated with OCD include:

  • Fear of being contaminated with dirt or germs;
  • Fear of harm;
  • Fear of making a mistake;
  • A need for things to be symmetrical or exact, and;
  • Intrusive thoughts and images about religion, sex or violence.


Compulsions are behaviors that are carried out according to specific rules. A person with OCD may feel an intense need to carry out certain actions to try and relieve the anxiety that builds up from their obsessive thoughts. Some people with OCD may believe that if they do not carry out certain actions, something bad will happen. Carrying out a compulsion may provide temporary relief from the obsessive thoughts and anxiety.

Some common compulsive behaviors that are associated with OCD include:

  • Washing hands;
  • Cleaning;
  • Checking (e.g. stove, locks, light switches);
  • Ordering and arranging, and;
  • Counting.

Someone with OCD may spend hours of their day carrying out these activities, over and over again.

The cycle of obsessive-compulsive disorder thoughts of germs lead to a person looking anxious, then washing their hands and sighing with temporary relief.The cycle of obsessive compulsive disorder. 


Most people with OCD realize that their thoughts and behaviors are not normal and feel embarrassed about their condition. This may lead to people deliberately avoiding things or places that trigger their obsessive thoughts. This can be debilitating, as some people may avoid leaving their home, or carrying out normal daily activities.


A feeling of tension, nervousness and dread about future events. It can trigger physical symptoms such as a rapid pulse or breathing difficulties.

Types of treatment

There is no cure for OCD, but there is treatment available to help people manage the condition. It is usually treated with a combination of medication and therapy.


The symptoms of OCD may be reduced with medication known as antidepressants. These work by helping to restore the balance of chemicals in the brain that affect a person's mood. Common antidepressants used to treat OCD include selective serotonin re-uptake inhibitors (SSRIs) such as paroxetine.

Antidepressants generally need to be taken for at least two weeks before any improvement in symptoms is noticed. Medication may also need to be continued even after the symptoms have disappeared, to prevent them from coming back. When stopping antidepressant medication, the dose usually needs to be reduced gradually over time to prevent any withdrawal responses.

Side effects

As with many medications, some people may experience some side effects when taking antidepressants. Some common side effects include nausea, dizziness and tiredness. Some antidepressants can have more serious side effects if they are taken with certain other medications or herbal remedies, or when combined with alcohol. A doctor will work with their patient to find the medication that is best for them.

Very rarely, some antidepressants may increase suicidal thoughts and the risk of suicide. The risk is highest in the first week after starting antidepressant treatment, or when the dose of antidepressants is changed. If someone experiences suicidal thoughts, it is important to contact a doctor immediately.


A common type of psychotherapy that is used to help manage OCD is called cognitive behavior therapy. This is a type of 'talking therapy' that aims to teach people with OCD how to change their thinking patterns and gain control over their compulsions and anxiety. Cognitive behavior therapy may also involve gradually exposing a person with OCD to situations that usually trigger their obsessions and helping to reduce their anxiety and compulsions.

A young woman in a session with a therapist.Cognitive behavior therapy aims for positive changes in thinking. 

Support groups

Attending support groups allows people affected by OCD, as well as their families, to learn more about the condition and how to manage it.


Medication used to treat depression and other mood disorders.


A feeling of tension, nervousness and dread about future events. It can trigger physical symptoms such as a rapid pulse or breathing difficulties.

Cognitive behavior therapy

A psychological or 'talking' therapy that focuses on changing unhelpful thoughts and behaviors that are causing a person distress.

Potential complications

OCD is a disabling condition that is often associated with other mental health conditions, such as depression and other anxiety disorders. Without treatment, OCD can affect a person's ability to carry out everyday tasks and activities and interfere with their relationships with family and friends.


A feeling of tension, nervousness and dread about future events. It can trigger physical symptoms such as a rapid pulse or breathing difficulties.


OCD is a long-term condition that usually requires lifelong management. With treatment, most people with OCD will be able to better manage or eliminate their symptoms.

There is no known way to prevent OCD. Recognizing the signs of the condition and seeking treatment early may help prevent it from getting worse.

FAQ Frequently asked questions