Obsessive Compulsive Disorder (OCD)

Tina's story

Tina was a teenager when she started to notice features of her OCD. She would worry a lot that she might be responsible for hurting people by something she did or didn't do. She would spend a lot of time going over in her mind to check whether she had hurt anyone, or whether she had made a mistake which could lead to anyone getting hurt. Tina had a number of rituals which helped to calm her. One of these was to tap her fingers on things an even number of times - she would do this until it felt 'right'. Tina got to the point where she was spending up to six hours a day on her behaviours or going through things in her mind.

Frank's story

Frank would experience many different kinds of obsessions. When he was around people he loved he would have vivid intrusive images of doing harm to them. He thought of himself as a peaceful man so he found this extremely upsetting, and it scared him to think that he might act on the images. Frank would also become obsessed by the idea that he was contaminated by germs, particularly from shared items at work, and would feel unclean. He would spend over two hours each day washing his hands and arms until he was satisfied that he was clean.

What is OCD?

A diagnosis of OCD is given when specific symptoms are present most days for the last 2 successive weeks, and must cause significant distress or interference with other activities.

  • Obsessions
    • Obsessions are recurrent and persistent thoughts, urges, or impulses
    • These are experienced as intrusive and unwanted, and tend to provoke anxiety
    • The response to the obsessions is to try to suppress them, or neutralise them with some other thought or action
  • Compulsions
    • Compulsions are repetitive behaviours or mental actions that the person feels driven to perform in response to an obsession
    • The compulsions are aimed at reducing anxiety or mental distress

Obsessions & intrusive thoughts

Unintended and unwanted thoughts are a common feature of being human. Our brains are constantly thinking - we can't help it! Some of our thoughts are deliberate - for example if you lose your keys and deliberately think back to where you last had them. Other thoughts are automatic - for example you can allow your mind to 'free associate' to the following words: tiger, color, book. Just notice what other thoughts or images come to mind.

Obsessions in OCD tend to follow common themes. Some of the most common obsessions are:

Losing control Contamination Sexual
Impulse to harm self By bodily fluids Unwanted sexual thoughts or images
Impulse to harm someone else By a chemical Sexual obsessions about children
Impulse to shout something obscene By germs or disease Sexual obsessions about homosexuality
Harm Religion Perfectionism
Being responsible for something awful (e.g. fire, accident) Worry about offending God Need to know or remember
Fear about hurting others by not being careful enough Concern about morality Concern with exactness or preciseness

Human beings not only have thoughts, they also have thoughts-about-having-thoughts. In OCD it is often these thoughts-about-thoughts' that lead to a strong emotional reaction.

Intrusive thoughts and images lead to more thoughts and emotions


Compulsions are actions, rituals or behaviours that are done to relieve the anxiety or distress caused by the obsessions. Compulsions can can be overt or external (visible things we do in the outside world) or covert or internal (things we do in our own minds). They are usually done to prevent harm from happening to the self, or to someone close. The person with OCD might realise that their actions are not rational, but they feel compelled to carry them out anyway. Common compulsions include:

Checking Washing & cleaning
Checking you did not harm your self or someone else Washing hands excessively
Checking nothing terrible happened Cleaning house or items obsessively
Checking you did not make a mistake Excessive washing, bathing, grooming
Mental compulsions Repeating
Praying to prevent harm Repeating activities
'Cancelling' a bad word or thought with a 'good' one Repeating body movements
Counting and ending on 'right' or 'good' number Repeating a mental event

What keeps OCD going?

The content of everybody's OCD is different, but there are often similar processes going on underneath. A key part of understanding OCD is thinking about what the obsessions mean to the person with OCD. In the example below, because the person has an intrusive thought about stabbing someone they interpret it to mean "Having the thought means I'm likely to act on it" and "I'm dangerous".

Cognitive behavioural formulation of OCD

How can I overcome my OCD?

1. Learn about intrusive thoughts

Intrusive thoughts are normal and everybody has them. We don't normally have many opportunities to talk about our intrusive thoughts with other people though, and we might keep them to ourselves for fear of what other people might think.

This page on Reddit is for people to post their intrusive thoughts. Their definition is:

[This is] A subreddit [place] for you to share all those intrusive, obsessive and recurring thoughts or ideas that race through your head throughout the day. Intrusive thoughts are random or recurring thoughts you have that make you want to do crazy things, such as "hit him with your car & jump off the building."

The content changes all the time. A selection of the intrusive thoughts from September 2014 included:

  • One of six people carrying a coffin into this funeral? Lets imagine a massive variety of ways you could drop it onto various mourners in attendance.
  • I wonder if I could beat up this teacher.
  • I am going through screening at the airport, I should say "I swear to Allah I am not a terrorist".
  • Fighting the urge to swallow my wedding ring. I should cut my fingertips off.
  • Whenever I have a thought that sounds like it could be dirty, I always clarify that it's not just in case anyone is reading my mind

2. Learn about thought suppression

One very common misconception is that we can control our thoughts. Put simply, we can't. Our brains are thinking machines - they spend a lot of time planning, judging, thinking, and worrying. Some of this we do deliberately, but much of it happens automatically.

3. Learn about typical cognitions and cognitive biases in OCD

A cognitive bias is sometimes called a thinking error or an unhelpful thinking style. Different cognitive biases are associated with different conditions. For example, depression is associated with a negativity bias (failure to see positive information) and panic is associated with catastrophic misinterpretation (worst outcomes seen as probable even if they are unlikely). OCD has been associated with a number of cognitions and cognitive biases:

  1. Having a thought about an action is morally equivalent to performing the action
  2. If a thought comes to mind, this means that this thought is likely to come true (this is sometimes called thought-action fusion)
  3. If a thought comes repeatedly to mind, it must have some special meaning
  4. Failing to prevent harm is the same as having caused the harm in the first place
  5. One can and should exercise control over one's thoughts (beliefs about controllability of thoughts)
  6. Inflated responsiblity - in OCD it is common to have an exaggerated belief in one's ability to produce or prevent negative outcomes
  7. Perfectionism - the idea that there is a right way to do everything and that I must do it that way
  8. Threat overestimation - a tendency to overestimate the likelihood or danger or harm
  9. Intolerance of uncertainty - the belief that it is necessary to be certain and the one must be certain in order to cope

(Selected cognitive biases from Thought Suppression by Eric Rassin and the Obsessive-Compulsive Cognitions Working Group [1997])

4. Monitor your obsessions and compulsions

First you have to know what you are up against. Use this OCD diary to record situations (triggers) as well as your obsessions and compulsions.

OCD Diary


5. Exposure and Response Prevention (EX/RP)

Exposure and Response Prevention is about exposing yourself to a situation that triggers your obsessions or compulsions (exposure), and then deliberately resisting the urge to carry out the compulsion that would normally relieve your anxiety (response prevention). It will be anxiety provoking to do this, and the anxiety will persist for some time to begin with, but it will decrease with time. In order to be successful with EX/RP you need to be consistent, and to have prolonged contact with your trigger until the feelings become manageable.

It is common to make a list of list of anxiety-provoking situations called a 'hierarchy'. Then you can start at the bottom, with the least anxiety-provoking, and work your way up.

6. Behavioral experiments to test predictions

Behavioral experiments are ways of finding out information, or testing out theories. They can help us to work around our cognitive biases. For more information read the section about how to carry out effective behavioral experiments.

Behavioural experiments in OCD might try to target some of the problematic beliefs in section (3) above. They might include:

(Some of the above behavioural experiments were adapted from The Oxford Guide to Behavioural Experiments in Cognitive Therapy edited by Bennett-Levy, Butler, Fennell, Hackman, Mueller, & Westbrook)

OCD worksheets

Intrusive thoughts are completely normal. It is also normal to think we can suppress them, but that is not necessarily the case.

Anxiety can set of the 'fight or flight response' or 'threat system'. This is an automatic reaction that human (and other animals) have to make then function at their best when they are threatened or in danger.

Record triggers, obsessions, and compulsions.

Make a list of situations that you find anxiety-provoking, or which trigger your OCD.

Exposure and Response Prevention is about exposing yourself to a situation that triggers your obsessions or compulsions (exposure), and then deliberately resisting the urge to carry out the compulsion that would normally relieve your anxiety (response prevention).

References and further reading

For more information about OCD the OCDUK.org website is a fantastic resource

The Intrusive Thoughts Subreddit is a place for people to share their intrusive thoughts