Obsessive compulsive disorder (OCD)

Last updated:

Reviewed by:

Dr Rhianna McClymont

, Lead GP at Livi

Medically reviewed

People with obsessive compulsive disorder (OCD) have frequent unwanted thoughts (obsessions) or feel the need to keep repeating certain actions (compulsions). Find out about what causes OCD and the signs and symptoms.

What is OCD?

OCD is a mental health condition that can affect you at any age. It causes obsessive thoughts and compulsive behaviour that can be time consuming and make day-to-day life unmanageable.

The obsessions and compulsions are likely to get worse when you’re feeling stressed or anxious about something else in your life, like your work, relationships or if you’re going through a period of change.

What causes OCD?

The exact cause of OCD isn’t clear, but research suggests that the following factors could play a part:

  • Personal experience – difficulties during childhood, like abuse, trauma or neglect, or stressful life events like giving birth or losing someone

  • Brain function – there’s some evidence that a lack of the chemical serotonin in the brain could be significant

  • Family – you’re at a higher risk of developing OCD if a close relative also has it

  • Personality – having certain personality traits, like being meticulous and methodical, could be linked to OCD

OCD symptoms

There are three main symptoms of OCD: obsessions, compulsions and emotions. Some people experience obsessions or compulsions on their own, but for most people, the three symptoms interplay and create a cycle that’s difficult to break.


Obsessions are ongoing thoughts, urges or concerns that play out again and again in your mind. Everyone experiences these from time to time, but when they dominate your thoughts and you’re unable to control them, it’s described as obsessive. This can be overwhelming and distressing.
Examples of common obsessive thoughts include:

  • Worrying that you’ll accidentally harm yourself or someone else if you’re not careful enough

  • Having violent thoughts or worrying that you’ll lose control and harm someone

  • Fear of your food being contaminated

  • Sexually disturbing thoughts

  • Worrying that something terrible will happen if things aren’t ordered in a certain way

Compulsions and emotions

When obsessions set in, it can feel scary and cause intense anxiety and stress.

These emotions often lead to ‘compulsive behaviour’ or actions that feel like they reduce anxiety. But the relief is usually only short-lived before obsessive thoughts creep back in, starting the cycle all over again.

Compulsive behaviour usually involves repeating a particular action until the thoughts begin to ease. You may worry that if you don’t complete this compulsive behaviour, you, or someone else, will be hurt in some way. You may also realise that your behaviour is illogical but be too scared to stop.

Compulsive behaviour can include:

  • Rituals like washing your hands, touching things in a certain way or ordering objects in a set way

  • Feeling the urge to keep checking things, like whether doors and windows are locked, or the oven is turned off

  • Counting or repeating words in your head

  • Needing repeated reassurance from others that everything is okay


It’s common for people with OCD to manage their anxieties for specific places or situations by avoiding them altogether. For example, if you worry about your food being contaminated, you might avoid eating in restaurants.

OCD diagnosis

If you’re experiencing obsessive thoughts or compulsive behaviour and it’s affecting your daily life, it’s essential to talk to a doctor. They’ll ask you about your symptoms and look at your medical history. You may be referred to a mental health specialist for an assessment.

It can be nerve-wracking to be honest about the range of thoughts and feelings you’re experiencing, especially if you feel guilty or ashamed about them. But the treatment you receive depends on how severe your OCD symptoms are, so it’s vital that your doctor fully understands the extent of your condition. This means they can give you the best treatment for your needs.

Sometimes, people with OCD also experience other mental health problems, like depression or eating disorders. If you have a history of these, or your doctor thinks you could have symptoms of another condition, they may want to explore it further in their assessments.

OCD treatment

Treatment for OCD is usually a combination of therapy and medication. Your treatment will depend on how severe your OCD is.

Talking therapy

Talking therapy normally involves cognitive behavioural therapy (CBT) and exposure and response prevention (ERP).

  • CBT helps you understand how your behaviour is affected by your thoughts and feelings.

  • ERP is designed for OCD and encourages you to face a situation that you fear deliberately. Your therapist will help you to tolerate the situation without resorting to compulsive behaviours.


Your doctor might recommend that you also take an antidepressant alongside talking therapy. This will usually be a type of antidepressant called a selective serotonin reuptake inhibitor (SSRI), which can help to boost serotonin levels in the brain.

Further support

OCD can be overwhelming and scary, and talking to others who understand what you’re going through can be a huge help. Self-help groups are a safe, private place where you can share your thoughts and feelings without judgement and get reassurance and advice. Talk to a doctor to find out what’s available in your area.

Last updated:
Reviewed by:
Dr Rhianna McClymont, Lead GP at Livi