Frequent handwashing is a behaviour often seen with OCD patients
**Obsessive–compulsive disorder** (**OCD**) is a mental disorder. It causes repeated and unwanted thoughts and/or feelings (obsessions). It causes repeated actions (compulsions). 

Anxiety is one of the most common symptoms. It can lead the person to believe that if a task is not done, something bad will happen. Such a task may be washing hands many times, keeping the lights on, or keeping their surrounding clean. This belief leads to more anxiety and tension. The actions that someone takes to stop the thoughts and feelings may take more than an hour every day. Excessive hand washing is a sign of OCD.

OCD can limit one's ability to take part in relationships, the workplace, and in society in general. OCD affects about 2% of the world's population. United States, about one in fifty adults has OCD.

Symptoms
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### Obsessions

Someone with obsessive–compulsive disorder has unwanted thoughts called obsessions. An obsession is an unwanted thought is happens many times. It is a thought that the person does not want to have. It is normal to have obsessions, but what changes is how people react to the thoughts. People who do not have OCD are able to ignore bad thoughts and move on, or such thoughts do not cause them much distress or anxiety. People who have OCD find it very hard to ignore these thoughts. However, just because someone has unwanted thoughts does not always mean they have OCD. Other brain-based disorders that could result in intrusive thoughts such as Bipolar disorder, Depression, Body dysmorphic disorder, and sometimes Attention-deficit hyperactivity disorder (ADHD).

Different people have different obsessive thoughts. Some people have obsessions about God, the Devil, or another religious figure hurting them or someone they love. Common obsessive thoughts for young people are about sex. They may think about things like kissing, having sex with, or touching people around them. People with OCD may carry this to extremes, or may worry that they may act on these thoughts.

Some people have obsessive–compulsive disorder without compulsions. This is called "primarily obsessional OCD", or "pure-O". It is thought that up to half of all people with obsessive–compulsive disorder have primarily obsessional OCD. People with primarily obsessional OCD may have a third type of obsession. This is aggressive thoughts. People with aggressive thoughts may have obsessions about hurting or killing themselves or people around them. Instead of performing compulsions, people with primarily obsessional OCD may act out compulsions in their mind or avoid the things and places that cause the obsessions.

### Compulsions

Many people with obsessive–compulsive disorder act in a certain way to stop the obsessive thought. These specific actions are known as compulsions. To someone with obsessive–compulsive disorder, doing these compulsions are a way to stop the obsessive thought. They may also think that doing the compulsion will stop something bad from happening to them or someone they care about.

Many compulsions are similar to body tics, and up to 40% of people with obsessive–compulsive disorder have a tic disorder. Some examples of compulsion include:

* Hand washing
* Cleaning themselves or things around them
* Doing something (like turning lights on and off) a certain number of times
* Putting objects in certain orders
* Counting to a certain number many times
* Checking that they did some action, usually checking a certain number of times

Many people mistakenly think OCD is only about organizing or cleaning, but it is more than just those two. For example, someone who has excessive fear of disappointing God, fear they will go to Hell upon death, or committing sins is scrupulous, which is OCD based on religion. Compulsions of someone who is scrupulous includes excessive praying, excessive trips to their church, asking their priest the same question if what they did is a sin even though they've been told it's not, etc.

People with obsessive–compulsive disorder usually know that their compulsions do not make sense, but do them anyways to stop the feelings of panic or anxiety. People with obsessive–compulsive disorder may do their compulsions for hours every day. Their compulsions can also hurt them, such as compulsive hand washing making their hands red and cut.

Causes
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The cause of obsessive–compulsive disorder is unknown. There is evidence that genes have a strong role in developing the disorder. If the disorder starts in childhood, it is more likely that other family members will have OCD than if the disorder starts in adulthood. It is thought that obsessive–compulsive disorder is the result of things humans did when they were evolving. Stress-inducing events also make OCD more severe.

Diagnosis
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There are four DSM diagnostic criteria for obsessive–compulsive disorder:

1. The person has to have obsessions, compulsions, or both. The DSM defines obsessions as thoughts that happen multiple times that the person does not want. The person has to try to get rid of the thoughts. The DSM defines compulsions as actions done multiple times because of an obsession. These actions are done to reduce the stress caused by an obsession.
2. The obsessions or compulsions take a lot of time or cause lots of problems in the person’s life.
3. The symptoms are not caused by a drug or a different medical problem.
4. The problems are not closer to the problems caused by other mental disorders such as an anxiety disorder or body dysmorphic disorder.

### Differential diagnosis

There is a mental disorder with a name similar to obsessive–compulsive disorder called Obsessive–Compulsive Personality Disorder or OCPD. However, these two conditions have very different symptoms. OCPD is a persistent pattern of rigidity and perfectionism. It does not have the obsessions and compulsions that define OCD. In fact, it is possible to have both disorders. 

Other differential diagnosis involve anxiety disorders (such as generalized anxiety disorder), major depressive disorder, eating disorders and psychotic disorders.

Management
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### Therapy

Behavioral therapy and cognitive behavioral therapy are used to help people with obsessive–compulsive disorder. The therapy works by making people be in places where they have their obsessive thoughts. They are then made to not do their compulsion. Over time, the person becomes used to the place or things that causes them to have their obsessive thoughts. An example of this is someone who is afraid of dirt having dirt put on their hands without being able to wash it off.

### Medication

The medicines that are usually used are called "selective serotonin reuptake inhibitors", or SSRIs. These medicines work by stopping a chemical in the brain called serotonin from working. This causes the obsessive thoughts to happen less. In adults, SSRIs are used for people with moderate or severe issues. In children, SSRIs are used after or with therapy for people with severe issues.

If SSRIs do not work, it is possible for a doctor to give someone with obsessive–compulsive disorder anti-psychotic medicines. Doctors may use both medication and counseling for those with the disorder, and they find that this approach works best.

### Procedures

Surgery can be used to help people if other treatments do not work. In the United States, surgery is not done unless medicine and therapy have not worked multiple times. In the United Kingdom, surgery cannot be done unless cognitive behavioral therapy has not worked.

### Children

Therapy can be used to reduce the compulsions in children and young adults. Family involvement is very important in treating children. Family also can give the child positive reinforcement for not doing their compulsive behaviors.

History
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In Europe from the 14th to 16th centuries, it was thought that people who had obsessive thoughts were possessed. They would treat these people by performing sometimes dangerous exorcisms to remove the Devil or evil spirit from the person. In the 1910s, a doctor named Sigmund Freud said that obsessive–compulsive disorder was because of fighting in someone's head. He said that these fights start in childhood when someone gains a "touching phobia", which fights with the natural want to touch things.

Well-known people with OCD
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John Bunyan (1628–1688), the author of *The Pilgrim's Progress*, showed symptoms of OCD. At that time, the condition did not have the name OCD. During the most severe period of his condition, he would mutter the same phrase over and over again to himself while rocking back and forth. He later described his obsessions in his autobiography *Grace Abounding to the Chief of Sinners*. He wrote in the book: "These things may seem ridiculous to others, even as ridiculous as they were in themselves, but to me they were the most tormenting cogitations." He wrote two pamphlets advising those with similar anxieties. In one of them, he warns against indulging in compulsions: "Have care of putting off your trouble of spirit in the wrong way: by promising to reform yourself and lead a new life, by your performances or duties".

British poet, essayist and lexicographer Samuel Johnson (1709–1784) also had OCD. He had elaborate rituals for crossing the thresholds of doorways, and repeatedly walked up and down staircases counting the steps. He would touch every post on the street as he walked past, only step in the middles of paving stones, and repeatedly perform tasks as though they had not been done properly the first time.

The American aviator and filmmaker Howard Hughes is known to have had OCD. Friends of Hughes have also mentioned his obsession with minor flaws in clothing. This was conveyed in *The Aviator* (2004), a film biography of Hughes.

English singer-songwriter George Ezra has openly spoken about his life-long struggle with OCD, particularly primarily obsessional obsessive–compulsive disorder (Pure O).

World renowned Swedish climate activist Greta Thunberg is also known to have OCD, among other mental health conditions.

American actor James Spader has also spoken about his OCD. In 2014, when interviewed for *Rolling Stone* he said: "I'm obsessive-compulsive. I have very, very strong obsessive-compulsive issues. I'm very particular. ... It's very hard for me, you know? It makes you very addictive in behavior, because routine and ritual become entrenched. But in work, it manifests itself in obsessive attention to detail and fixation. It serves my work very well: Things don't slip by. But I'm not very easygoing.

In 2022 the president of Chile Gabriel Boric stated that he had OCD, saying: "I have an obsessive–compulsive disorder that's completely under control. Thank God I've been able to undergo treatment and it doesn't make me unable to carry out my responsibilities as the President of the Republic."

Society and culture
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There are several movies and television shows that show people with obsessive–compulsive disorder. The movie *The Aviator* shows the life of Howard Hughes. Hughes was afraid of germs, and his obsessions and compulsions were about keeping germs away. English footballer David Beckham has talked about his obsessive–compulsive disorder. Television hosts Howie Mandel and Marc Summers have also talked about their obsessions and compulsions.