Obsessive compulsive disorder (OCD) affects people differently, but usually causes a particular pattern of thoughts and behaviours.

OCD has 3 main elements:

• obsessions – where an unwanted, intrusive and often distressing thought, image or urge repeatedly enters your mind
• emotions – the obsession causes a feeling of intense anxiety or distress
• compulsions – repetitive behaviours or mental acts that a person with OCD feels driven to perform as a result of the anxiety and distress caused by the obsession

The compulsive behaviour temporarily relieves the anxiety, but the obsession and anxiety soon return, causing the cycle to begin again.

It's possible to just have obsessive thoughts or just have compulsions, but most people with OCD experience both.

Obsessive thoughts

Almost everyone has unpleasant or unwanted thoughts at some point, such as thinking they may have forgotten to lock the door of the house, or even sudden unwelcome violent or offensive mental images.

But if you have a persistent, unpleasant thought that dominates your thinking to the extent it interrupts other thoughts, you may have an obsession.

Some common obsessions that affect people with OCD include:

• fear of deliberately harming yourself or others – for example, fear you may attack someone else, such as your children
• fear of harming yourself or others by mistake – for example, fear you may set the house on fire by leaving the cooker on
• fear of contamination by disease, infection or an unpleasant substance
• a need for symmetry or orderliness – for example, you may feel the need to ensure all the labels on the tins in your cupboard face the same way

You may have obsessive thoughts of a violent or sexual nature that you find repulsive or frightening. But they're just thoughts and having them does not mean you'll act on them.

Compulsive behaviour

Compulsions starts as a way of trying to reduce or prevent anxiety caused by the obsessive thought, although in reality this behaviour is either excessive or not realistically connected.

For example, a person who fears contamination with germs may wash their hands repeatedly, or someone with a fear of harming their family may have the urge to repeat an action multiple times to "neutralise" the thought.

Most people with OCD realise that such compulsive behaviour is irrational and makes no logical sense, but they cannot stop acting on it and feel they need to do it "just in case".

Common types of compulsive behaviour in people with OCD include:

• cleaning and hand washing
• checking – such as checking doors are locked or that the gas is off
• counting
• ordering and arranging
• hoarding
• asking for reassurance
• repeating words in their head
• thinking "neutralising" thoughts to counter the obsessive thoughts
• avoiding places and situations that could trigger obsessive thoughts

Not all compulsive behaviours will be obvious to other people.

Getting help

It's important to get help if you think you have OCD and it's having a significant impact on your life.

If you think a friend or family member may have OCD, try talking to them about your concerns and suggest they get help.

OCD is unlikely to get better on its own, but treatment and support is available to help you manage your symptoms and have a better quality of life.

There are 2 main ways to get help:

• refer yourself directly to a psychological therapies service – find a psychological therapies service in your area
• see a GP – they'll ask about your symptoms and can refer you to a local psychological therapies service if necessary

Contact your GP or care team immediately if you ever feel you cannot go on. You can also phone the Samaritans on 116 123 or one of these other helplines and support groups or contact NHS 111.

Related problems

Some people with OCD may also have or develop other serious mental health problems, including:

• depression – a condition that typically causes lasting feelings of sadness and hopelessness, or a loss of interest in the things you used to enjoy
• eating disorders – conditions characterised by an abnormal attitude towards food that cause you to change your eating habits and behaviour
• generalised anxiety disorder – a condition that causes you to feel anxious about a wide range of situations and issues, rather than one specific event
• a hoarding disorder – a condition that involves excessively acquiring items and not being able to throw them away, resulting in unmanageable amounts of clutter

People with OCD and severe depression may also have suicidal feelings.

Obsessive compulsive disorder (OCD) can be treated. The treatment recommended will depend on how much it's affecting your life.

The 2 main treatments are:

• psychological therapy – usually a type of therapy that helps you face your fears and obsessive thoughts without "putting them right" with compulsions
• medicine – usually a type of antidepressant medicine that can help by altering the balance of chemicals in your brain

A short course of therapy is usually recommended for relatively mild OCD. If you have more severe OCD, you may need a longer course of therapy and/or medicine.

These treatments can be very effective, but it's important to be aware that it can take several months before you notice the benefit.

You can get treatment on the NHS through your GP or by referring yourself directly to a psychological therapies service.

Find out more about psychological therapies on the NHS.

Psychological therapy

Therapy for OCD is usually a type of cognitive behavioural therapy (CBT) with exposure and response prevention (ERP).

This involves:

• working with your therapist to break down your problems into their separate parts, such as your thoughts, physical feelings and actions
• encouraging you to face your fears and have obsessive thoughts without neutralising them with compulsive behaviours; you start with situations that cause the least anxiety first, before moving on to more difficult thoughts

The treatment is difficult and may sound frightening, but many people find that when they confront their obsessions, the anxiety eventually improves or goes away.

People with fairly mild OCD usually need about 10 hours of therapist treatment, with exercises done at home between sessions. If you have more severe OCD, you may need a longer course of treatment.

Medicine

You may need medicine if psychological therapy does not help treat your OCD, or if your OCD is fairly severe.

The main medicines prescribed are a type of antidepressant called selective serotonin reuptake inhibitors (SSRIs). An SSRI can help improve OCD symptoms by increasing the levels of a chemical called serotonin in your brain.

You may need to take an SSRI for 12 weeks before you notice any benefit.

Most people need treatment for at least a year. You may be able to stop if you have few or no troublesome symptoms after this time, although some people need to take an SSRI for many years.

Do not stop taking an SSRI without speaking to your doctor first because suddenly stopping can cause unpleasant side effects. Treatment will be stopped gradually to reduce the chance of getting side effects. Your dose may need to be increased again if your symptoms return.

Side effects

Possible side effects of SSRIs include:

• feeling agitated, shaky or anxious
• feeling or being sick
• diarrhoea or constipation
• dizziness
• sleeping problems (insomnia)
• headaches
• low sex drive

There's also a very small chance that SSRIs could cause you to have suicidal thoughts or want to self-harm. If this happens, contact your GP or go to your nearest accident and emergency (A&E).

Most side effects improve after a few weeks as your body gets used to the medicine, although some can persist.

Pregnancy

SSRIs are not usually recommended during pregnancy, particularly during the first 3 months (1st trimester). This is because there may be a risk to the baby.

However, exceptions can be made if the risk posed by a mental health condition outweighs the potential risks of treatment.

Further treatment

Further treatment by a specialist team may sometimes be necessary if you've tried psychological therapy and medicine and your OCD is still not under control.

Some people with severe, long-term and difficult-to-treat OCD may be referred to a national specialist OCD service.

These services offer assessment and treatment to people with OCD who have not responded to treatments available from their local and regional OCD services.

OCD UK has more information about NHS Specialist OCD Treatment Services, including adult and child and adolescent services.

OCD support groups

Many people with OCD find support groups helpful, as they can:

• provide reassurance and coping advice
• reduce feelings of isolation 
• offer a chance to socialise with others
• provide information and advice for family members and friends

The national charities OCD Action, OCD-UK and TOP UK can provide information about support groups in your area:

• OCD Action support groups
• OCD-UK support groups
• TOP UK support groups

You may want to visit the HealthUnlocked OCD forum, where you can discuss all aspects of the condition with others who have OCD.

You can also find mental health apps and tools in the NHS apps library.