Obsessive-compulsive disorder (OCD): symptoms, causes and treatment

OCD has two linked parts. The NHS describes obsessions as unwanted and unpleasant thoughts, images or urges that repeatedly enter your mind and cause anxiety, disgust or unease, and compulsions as repetitive behaviours or mental acts that you feel you need to do to temporarily relieve those feelings. The Royal College of Psychiatrists lists common patterns, which also show how the two fit together.

• Contamination fears, leading to repeated washing, cleaning and avoiding places or people.

• Doubt and responsibility, leading to checking appliances, doors or the route taken.

• Needing things to be exactly right, balanced or in a particular order.

• Distressing thoughts or images, with mental rituals such as counting, praying or repeating a word to neutralise them.

• Seeking reassurance repeatedly from other people.

• Hoarding of worn-out or useless possessions.

The NHS defines OCD as a mental health condition in which a person has obsessive thoughts and compulsive behaviours. An obsession is an unwanted and unpleasant thought, image or urge that repeatedly enters the mind and brings anxiety, disgust or unease. A compulsion is a repetitive behaviour or mental act the person feels they need to do to relieve those feelings temporarily. The NHS example is a person with an obsessive fear of being burgled who feels they must check all windows and doors several times before leaving the house.

The everyday word obsessive is used loosely, but the clinical meaning is narrow. The Royal College of Psychiatrists says that, unlike habits such as gambling or shopping, the compulsions in OCD never give pleasure and are always felt as an unpleasant demand or burden. People with OCD also do not lose control, even though they often worry that they will, and having a harmful thought does not mean someone will act on it.

The NHS names two main treatments: talking therapy, usually CBT, which helps you face your fears and obsessive thoughts without putting them right through compulsions, and SSRI antidepressants. CBT will usually have an effect quite quickly, while SSRIs can take up to 12 weeks before benefits are noticed, though most people eventually benefit. If these do not help, the NHS says you may be offered an alternative SSRI, an SSRI together with CBT, or clomipramine, and some people are referred to a specialist service.

The Royal College of Psychiatrists describes the main CBT approach, exposure and response prevention (ERP). You gradually face a feared situation while resisting the usual ritual, and stay with it until anxiety falls, working up a ladder of fears from the least to the most distressing. It reports that about 3 out of 4 people who complete ERP are helped a lot, that about 1 in 4 refuse or do not finish it, and that about 1 in 5 of those who get better develop symptoms again and need extra treatment. Cognitive therapy, which changes the reaction to thoughts, can also be used alone or alongside ERP.

For medicines, the Royal College says SSRIs reduce obsessions and compulsions even when a person is not depressed, higher doses often work better for OCD, and about 6 out of 10 people improve, with symptoms reducing by about one third on average. If an SSRI has not helped at all after 3 months, the next step is to change to another SSRI or to clomipramine, and medicine is best continued for at least 12 months if it is helping. About 1 in 3 who stop medication relapse in the following months, which is less likely when it is combined with CBT. Medicines should be reduced slowly rather than stopped suddenly, and dose decisions belong to the prescriber.

The NHS says OCD can affect men, women and children, with symptoms from as early as 6 years old and often beginning around puberty and early adulthood. The Royal College of Psychiatrists says adult OCD usually begins in the teens or early twenties and that many people do not seek help until they have had it for many years. It also notes that about 1 in 50 people have OCD at some point, men and women equally. OCD-UK, a charity, says around three quarters of a million people in the UK are thought to be living with severe, life-impacting OCD.

OCD can occur during pregnancy or after birth, when obsessions might involve fears about harming the baby or not sterilising feeding bottles properly, and compulsions such as repeatedly checking the baby is breathing, according to the NHS. It advises speaking to a GP or health visitor.

The NHS says it is not clear what causes OCD, and lists possible contributors: family history, differences in the brain, such as low levels of the chemical serotonin, life events such as bullying, abuse, neglect, childbirth or bereavement, and personality, such as being meticulous with high personal standards or having a strong sense of responsibility. The Royal College of Psychiatrists adds that stressful life events bring OCD on in about one or two out of every three cases, and that the way people respond to intrusive thoughts can keep the cycle going.

That last point matters for treatment. Nearly everyone has odd or distressing thoughts at times. The Royal College explains that people with high standards of morality and responsibility may feel it is terrible even to have such a thought, watch for it to return, and so make it return more often. Pushing thoughts away, neutralising them or performing rituals gives short-term relief but strengthens the belief that the ritual prevents harm.

The NHS describes two main routes: refer yourself directly to an NHS talking therapies service, or see a GP, who will ask about your symptoms and can refer you to a local talking therapies service if needed. If you are under 18, or seeking help for someone under 18, the NHS points to children and young people's mental health support. The NHS stresses that OCD is a health condition like any other, with nothing to be ashamed or embarrassed about.

If a friend or family member may have OCD, the NHS suggests talking to them about your concerns and suggesting they get help. The Royal College advises that family can help by encouraging them to tackle fearful situations, saying no to taking part in rituals and avoiding repeated reassurance, but not physically preventing a ritual.

The Royal College says a GP can refer on to a specialist team including psychiatrists, psychologists, nurses and occupational therapists. They may suggest adding cognitive therapy, combining two anti-obsessional medicines, adding an antipsychotic, treating linked conditions such as anxiety, depression or alcohol problems, which affect about 1 in 3 people with OCD, and supporting family and carers. For a very small number with severe OCD that has not improved, intensive inpatient programmes are available, and deep brain stimulation and neurosurgery are described as rarely offered last resorts.

Private therapists are an option for people who wish to avoid waiting lists, and OCD-UK warns that anybody can call themselves a therapist, so it is worth checking registration, for example with the British Association for Behavioural and Cognitive Psychotherapies. Costs differ widely between therapists.

OCD is treatable and is not usually an emergency, but distress can become severe. The NHS says to get advice from 111 (select the mental health option) or ask for an urgent GP appointment if you need urgent help for your mental health.

Call 999 or go to A&E if someone’s life is at risk, for example they have seriously injured themselves or taken an overdose, or you do not feel you can keep yourself or someone else safe. The NHS says a mental health emergency should be taken as seriously as a physical one. Samaritans can be reached on 116 123, free, at any time.

Having a harmful intrusive thought does not mean you will act on it. The Royal College of Psychiatrists says people with OCD do not lose control, but if you are worried about your thoughts, speak to your GP.