Though once considered fairly rare, obsessive compulsive disorder (OCD) is now thought of as a common form of anxiety disorder that affects around 1 in every 50 people in the UK at some point in their lives - that's more than a million people.

Anyone can develop it at any age, even during childhood (some develop the condition around the time of puberty). But according to the NHS, OCD typically develops during early adulthood. If you have OCD you'll have obsessive thoughts and compulsive behaviours, and if your symptoms are severe it could make everyday activities - including working, being in a relationship or taking part in family life - very difficult.

What are the symptoms?

According to the Royal College of Psychiatrists, OCD has 3 main parts: 

  1. Obsessions (or the thoughts that make you anxious
  2. The anxiety you feel as a result of having obsessions
  3. The things you do to reduce your anxiety - in other words, compulsions

Obsessions can take many forms. You may have unwanted and unpleasant thoughts, images, urges, worries or doubts that you can't get out of your head. Some common obsessions, says the NHS, include a need for symmetry or orderliness, a fear of harming yourself or others - either deliberately or by mistake - and a fear of contamination by disease or infection. You may also have obsessive thoughts of a violent or sexual nature. But according to the Royal College of Psychiatrists, people with obsessions don't become violent or act on their obsessive thoughts.

Having these thoughts can make you feel anxious, guilty, disgusted or distressed, and the only thing that can make you feel better or make you believe that something bad isn't going to happen is to carry out a compulsive behaviour multiple times.

These compulsions include rituals such as:

  • Cleaning and hand washing (if you fear you've been contaminated with germs, for instance)
  • Checking (such as making sure that appliances are switched off or that your house is locked)
  • Counting
  • Arranging things in order
  • Repeating words or phrases in your mind to 'neutralise' obsessional thoughts
  • Asking other people to tell you everything is alright
  • Hoarding possessions that are no longer useful
  • Avoiding things or places that you believe could trigger obsessive thoughts

Some people with OCD are also at risk of developing other mental health problems such as depression, eating disorders and generalised anxiety disorder.

What causes OCD?

Nobody really knows exactly what causes OCD, though some things are thought to make it more likely. These include having a family history of OCD and being under a lot of stress (according to experts at the Royal College of Psychiatrists, stressful life events bring on OCD in about 1 in 3 cases). Indeed, it's thought that most people experience OCD-type symptoms to some degree at 1 time or another, particularly at times of major stress.

Certain life stages can trigger OCD symptoms too, such as puberty, starting a new job, having a baby or a bereavement. And people who are very particular about things - neatness or being very methodical, for instance - may have personalities that make them more prone to OCD. Experts also think those who have OCD for longer periods may have an imbalance of a chemical called serotonin in their brain.

Meanwhile the severity of symptoms can vary greatly from 1 person to the next. According to OCD UK, 50% of people with OCD have severe symptoms, with less than a quarter classed as mild cases.

The good news is many people with mild OCD improve without any treatment. Those with more moderate or severe OCD tend not to improve without treatment, though they may find their symptoms go away at times then get worse when they're stressed or depressed.

In such cases treatment usually helps, says the Royal College of Psychiatrists. This usually comprises psychological therapy or medication, or in severe cases both.

According to the NHS, the type of therapy recommended for OCD is cognitive behavioural therapy (CBT) with exposure and response prevention (ERP). If you have OCD, ERP therapy can sound alarming as it encourages you to face the situations you fear and wait for your anxiety to disappear without doing your usual compulsive rituals. But experts believe 3 out of 4 people who complete ERP therapy are helped a lot.

If psychological therapy doesn't help - or if you have fairly severe OCD - you may need to take medication that increases the levels of serotonin in your brain.

How to get help

If OCD is controlling your life it's important to get treatment, as only the mildest cases get better on their own. Treatment is available on the NHS through your GP, who can refer you to a local psychological therapy service. Depending on where you live, you may also be able to refer yourself to a local psychological therapy service.

Many people with OCD also find joining a support group helpful, as it can make them feel less isolated and may give them the reassurance they need. There are 3 national charities that provide details of local support groups:

If you think a friend or family member may have OCD, the NHS recommends talking to then about your concerns and suggesting they seek help.