NHS Lothian

Obsessive Compulsive Disorder (OCD)

2 min read

What is Obsessive Compulsive Disorder, or OCD?

OCD is short for Obsessive Compulsive Disorder.  It’s a relatively common mental health difficulty which includes having difficult thoughts, uncomfortable feelings, and repetitive behaviours. The behaviours are often used as a way of coping with the difficult thoughts and feelings, however in OCD this way of coping becomes unhelpful.


What’s it like to have OCD?

People with OCD usually experience frequent obsessive thoughts and compulsive behaviours.

  • An obsession is an unwanted and unpleasant thought, image or urge that repeatedly enters your mind, causing feelings of anxiety, disgust or unease.
  • A compulsion is a repetitive behaviour or mental act that you feel you need to do, in order to relieve the unpleasant feelings brought on by the obsessive thought. These behaviours or mental acts are sometimes called rituals.

The relief that people get from compulsive behaviours or rituals is typically short-lived. Often people find that the more they do these things, the more they need to do them. This can end up taking up a lot of time and can have a huge impact on everyday life.

What causes OCD?

There may be several different factors, including:

  • family history – you’re more likely to develop OCD if a family member has it, possibly because of your genes
  • differences in the brain – some people with OCD have areas of unusually high activity in their brain or low levels of a chemical called serotonin
  • life events – OCD may be more common in people who have been bullied, abused or neglected, and it sometimes starts after an important life event, such as childbirth or a bereavement
  • personality – neat, meticulous, methodical people with high personal standards may be more likely to develop OCD, also people who are generally quite anxious or have a very strong sense of responsibility for themselves and others.


Here are some of the most common thoughts:


Thoughts about yourself

  • “I need to control these distressing thoughts”
  • Intrusive sexually explicit or violent thoughts and images
  • A focus on religious or moral ideas
  • “I’m going mad”


Thoughts about other people

  • “I need to do my rituals in order to keep my family/friends safe”
  • “I’m worried I could lose control and harm people around me”
  • “If people knew, they would think I’m mad/bad/dangerous”


Thoughts about the future

  • Worries about losing control
  • Worries about losing or not having things you might need
  • Worries about going mad


Thoughts about the future

  • “The world is dangerous/dirty”
  • Thoughts about being contaminated by germs or dirt or contaminating others
  • Order and symmetry: the idea that everything must line up “just right”
  • Superstitions: excessive attention to something considered lucky or unlucky


How common is OCD?

It’s been estimated that OCD affects between 1% and 2% of the general population. However, OCD usually has an impact on the people around you too, so the percentage of the population affected by OCD is likely to be considerably higher.

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