What is obsessive-compulsive disorder (OCD)?

Obsessive-compulsive disorder (OCD) is described as an anxiety disorder.The condition has two main parts: obsessions and compulsions.

Obsessions are unwelcome thoughts, images, urges or doubts that repeatedly appear in your mind; for example, thinking that you have been contaminated by dirt and germs, or experiencing a sudden urge to hurt someone.
These obsessions are often frightening or seem so horrible that you can’t share them with others. The obsession interrupts your other thoughts and makes you feel very anxious.

Compulsions are repetitive activities that you feel you have to do. This could be something like repeatedly checking a door to make sure it is locked or repeating a specific phrase in your head to prevent harm coming to a loved one.
The aim of a compulsion is to try and deal with the distress caused by the obsessive thoughts and relieve the anxiety you are feeling. However, the process of repeating these compulsions is often distressing and any relief you feel is often short-lived.

-The OCD cycle
The diagram below shows how obsessions and compulsions are connected in an OCD cycle.

Living with OCD
Although many people experience minor obsessions (e.g. worrying about leaving the gas on, or if the door is locked) and compulsions (e.g. rituals, like avoiding the cracks in the pavement), these don’t significantly interfere with their daily lives, or are short-lived.

If you experience OCD, your obsessions and compulsions will cause you considerable fear and distress. They will also take up a significant amount of time, and disrupt your ability to carry on with your day-to-day to life, including doing daily chores, going to work, or maintaining relationships
with friends and family.

Many people with OCD experience feelings of shame and loneliness which often stop them from seeking help, particularly if they experience distressing thoughts about subjects such as religion, sex or violence. This means that many people try to cope with OCD alone, until the
symptoms are so severe they can’t hide them anymore.OCD is also known to have a close association with depression, and some people find obsessions appear or get worse when they are depressed.

What are the common signs of OCD?

Although everyone will have their own experiences, there are several common obsessions and compulsions that occur as part of OCD.

Common obsessions
The three most common themes are: unwanted thoughts about harm or aggression, unwanted sexual thoughts and unwanted blasphemous thoughts. Obsessions often appear closely linked to your individual situation. For example, if you are a loving parent, you may fear doing harm to a child and if you are religious, you may have blasphemous thoughts.

Some examples of obsessions include:
• a fear of failing to prevent harm – e.g. worrying that you have left the cooker on and might cause a fire.
• imagining doing harm – e.g. thinking that you are going to push someone in front of a train.
• intrusive sexual thoughts – e.g. worrying about abusing a child.
• religious or blasphemous thoughts – e.g. having thoughts that are against your religious beliefs.
• fear of contamination – e.g. from dirt and germs in a toilet
• an excessive concern with order or symmetry – e.g. worrying if objects are not in order
• illness or physical symptoms – e.g. thinking that you have cancer when you have no symptoms.

Common compulsions
Common compulsions include physical compulsions, e.g. washing or checking, or mental compulsions, e.g. repeating a specific word or phrase.

Some examples might be:
• repeating actions – e.g. touching every light switch in the house every time you leave or enter the house.
• touching – e.g. only buying things in the supermarket that you have touched with both hands.
• focusing on a number – e.g. having to buy three of everything.
• washing or cleaning – e.g. having to wash your hands very frequently in order to feel clean.
• checking – e.g. reading through an email ten times before sending it.
• ordering or arranging – e.g. keeping food organised by colour in the fridge.
• repeating a specific word or phrase – e.g. repeating someone’s name in order to prevent .something bad happening to them.
• praying – e.g. repeating a prayer again and again whenever you hear about an accident.
• counteracting or neutralising a negative thought with a positive one – e.g. replacing a bad word with a good one.

You might find that some objects or experiences make your obsessions or compulsions worse, and you try to avoid them as a result. For example, if you fear contamination, you might avoid eating and drinking anywhere except in your own home. Avoiding things can have a major impact on your life.

What causes OCD?
There are different theories about why OCD develops, but none of these theories have been found to fully explain every person’s experience.

‘Dysfunctional’ beliefs
One theory suggests that OCD develops because of ‘dysfunctional’ beliefs and interpretations.
If you experience OCD, you might believe that you have more responsibility for a situation than you actually do. Because of this, your reaction may be out of proportion. For example, many people experience sudden and intrusive thoughts, such as thinking that they might push someone in front of a train on a crowded platform. Most people dismiss it as a passing thought and do not believe they would actually do it.However, if you have OCD, you are more likely to believe that you might
act on the thought. This makes you anxious or scared, and so you maythen develop a compulsion to try and prevent it happening. This could start an OCD cycle.

Personal experience
Some psychological theories suggest that OCD is caused by personal experience. It is thought that if you have had a painful childhood experience or suffered trauma or abuse, you might learn to use obsessions and compulsions to cope with anxiety. However, this theory does not explain why people who cannot point to any painful experiences might experience OCD.

It could also be that one or both of your parents may have had similar anxiety and shown similar kinds of behaviour (such as obsessional washing), and you learned to use this type of behaviour as a coping technique.

Biological factors
Some biological theories suggest that a lack of the brain chemical serotonin may have a role in OCD. However, experts disagree about what that role is, and it is unclear whether a lack of serotonin causes OCD or  is the effect of having the condition. Studies have also looked at genetic
factors and how different parts of the brain might be involved in causing OCD, but have found nothing conclusive.

However, biological theories do not provide any explanation for how the condition develops differently in different people; for example, why one person might develop a contamination obsession while another develops an obsession about harming.

Some experts have noted that some children seem to develop OCD symptoms very suddenly after having a streptococcal (or strep) infection, such as strep throat or scarlet fever. However, it is currently not known why this might occur and no research has yet been able to identify a
physical cause to explain the link.