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Obsessive compulsive disorder

About OCD

Obsessive-compulsive disorder (OCD) is a mental illness.

People with OCD have:

  • obsessions – unwanted thoughts about, for example, dirt and disease, terrible things happening, sex, violence, or religious themes
  • compulsions – overwhelming urges to do activities such as cleaning, checking, counting or praying.

The compulsions make a person with OCD feel (briefly) less guilty or anxious about their unwanted thoughts, which often disgust or horrify them.

The obsessive thoughts can be quite overwhelming, while compulsions can take up hours of a person’s day.

Around 1 in 100 Australians and New Zealanders will have OCD at some point in their life.

It can affect anyone of any age, and usually starts in childhood.

People with OCD will often hide their illness from others. But there are effective treatments available and you should seek help if you are worried about yourself or a loved one.

Causes of OCD

The exact cause of OCD is unknown. There is some evidence that OCD runs in families, but more research needs to be done in this area.

Signs and symptom­­s

You might notice:

  • constant intrusive, unwanted thoughts or mental images
  • washing hands often
  • cleaning clothes, house or belongings a lot
  • putting things in a particular order
  • counting, repeating words, tapping or praying
  • checking things – door locks, appliances, taps
  • feeling you have to do things over and over again to make sure
  • constantly asking people for reassurance
  • having routines and rituals that you have to follow every day
  • being aware that your thoughts are irrational but being unable to stop the thinking.

OCD can come and go, and the symptoms can get better or worse over time.

A diagnosis of OCD can only be made by a doctor or clinical psychologist.

If you notice any of these symptoms and they are affecting your daily life, you should seek help.

Help for OCD

As a first step, see your GP.

A GP can assess your symptoms and refer you to see a psychiatrist or psychologist if you need it.

Mental illness: first steps to get help

Treatment of OCD

OCD can be treated effectively with psychological treatments (talking therapies) and, in some cases, medication.

Exposure and response prevention therapy (ERP)

ERP is the most effective psychological treatment for OCD. A psychiatrist or psychologist can guide and support you.

In ERP, you begin by making a list of activities that make you anxious. You order them on a scale, from easiest to most difficult. Then, starting at the easiest activity, you go ahead and do it, with the help of your therapist.

During the activity you will be encouraged to experience the anxiety, refuse to perform a compulsion and wait for your anxiety level to slowly drop.

You repeat the activity until you become used to it. You then move on to the next task or situation.

Here is an example from someone whose OCD has a focus on a fear of dirt and disease, rated from 20 (least anxiety) to 100 (most anxiety).

100 public toilets

99 toilets generally

95 wheelie bins

90 kitchen and bathroom bins

85 mop and bucket

80 dirty washing

75 ground outside

70 floors

60 shaking hands

50 letters and money

40 telephone

30 light switches

30 door handles

20 cords on blinds

Reproduced with permission from Blair-West RS et al. (2016) The Obsessive Compulsive Disorder Program Workbook. The Melbourne Clinic.

ERP is proven to be very effective at reducing the symptoms of OCD in the long term.

Medication for OCD

The most common type of medication used for OCD is a selective-serotonin reuptake inhibitor (SSRI). An example of an SSRI is fluoxetine (sold under the brand name Prozac).

The medication works to reduce the intrusive thoughts and compulsions and any related depression.

Generally, medication is used to get you in a good mindset to tackle the ERP therapy.

Psychiatrist's role

Psychiatrists can:

  • make a diagnosis of OCD
  • diagnose and treat any depression or anxiety, which are common in people with OCD
  • provide treatments – ERP, other types of talking therapy and medication
  • provide referrals or recommend you see other health professionals – including occupational therapists, psychologists and community supports
  • admit you to hospital if needed.

 Find a psychiatrist near you who specialises in treating OCD

Recovery from OCD

Once you begin to recover, things you can do to help yourself are:

  • Continue to challenge yourself by facing situations that make you anxious.
  • Find fun activities to fill in your extra time.
  • Join a support group in-person or online.
  • Be aware of the signs of depression.

Relapse of OCD

OCD symptoms can come back.

Have a plan ready so you can act as soon as you notice yourself becoming unwell.

A plan will make it easier to cope with relapse and continue on your recovery journey.

Helping someone with OCD

Having a loved one with OCD can be stressful and frustrating.

Compulsions are not something that someone with OCD can just ‘stop doing’. They often hate the fact that they have no control over their compulsions and are mentally and physically exhausted from dealing with their OCD.

You can help by:

  • encouraging them to face situations that make them feel anxious
  • gently saying no if the person asks you to do their compulsion for them (for example, checking the stove is switched off)
  • going to appointments with them
  • encouraging them to get extra help if they are not coping.


  • OCD is a mental illness and there are effective treatments available.
  • Find a psychiatrist who specialises in treating OCD.
  • Challenge yourself during therapy to stick to your treatment plan.
Page last reviewed Apr 2021 | C1011V1

This is a general guide only, and does not replace individual medical advice. Please speak to your doctor for advice about your situation. The RANZCP is not liable for any consequences arising from relying on this information. Subject matter experts, people with lived experience of mental illness and carers all contributed to this fact sheet.