Obsessive-Compulsive Disorder

Obsessive-compulsive (ob-SES-iv-kom-PUL-siv) disorder (OCD) causes people to become trapped in a pattern of repeated, intrusive, unwanted thoughts, called obsessions (ob-SESH-unz), and a pattern of repetitive behaviors, called compulsions (kom-PUL-shunz). Thoughts that feel impossible to control cause distress and anxiety (ang-ZY-e-tee) that is often temporarily relieved by performing a particular compulsive behavior.

Melvin and Adrian

In the 1997 movie As Good As It Gets, actor Jack Nicholson portrays Melvin Udall, a man who acts in ways that seem odd to others. Melvin feels as if he has to eat lunch at the same table each day, and he always brings his own plastic utensils. He follows a complicated procedure to lock his front door. Much of what he does—from the way he walks around cracks to the way he talks and thinks—makes his life difficult. This character has obsessive-compulsive disorder. Adrian Monk, the main character on the television series Monk (played by Tony Shalhoub), also was portrayed as having OCD.

What Is Obsessive-Compulsive Disorder?

Many people knock on wood to ward off bad luck. Others may walk around, rather than under, ladders, or they may step over, rather than on, cracks in the sidewalk. These are familiar examples of superstitions and rituals. Superstitions are irrational beliefs resulting from false ideas, fear of the unknown, or trust in magic or chance. Superstitions are common in everyday life and generally are harmless. People with obsessive-compulsive disorder, however, go much further, to the point of becoming trapped in a pattern of repeated, unwanted behaviors and thoughts that are senseless and upsetting but that seem impossible to control. The behaviors and thoughts can take up so much time and energy that they interfere with the individual's daily life.

OCD is one of a group of disorders described in the DSM-5 *


PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections) is a term for unusual, OCD-like symptoms that arise in a small number of children under age 13 after a case of strep throat, a common throat infection caused by the Streptococcus bacteria. The behavior of the children usually changes quite suddenly. Almost overnight, they develop obsessions, compulsions, tics, and uncontrollable muscle twitches. As of 2016, PANDAS was thought to be an autoimmune disorder. In children who develop PANDAS, the Streptococcus bacteria causes an unusual and inappropriate response where the immune system attacks the body's own cells and causes damage to the brain, which results in PANDAS symptoms.

In an effort to prevent these thoughts, people may go through repeated rituals called compulsions. Common compulsions include hand washing, repetitive checking (for example that the door is locked or the stove is turned off), putting objects in order according to rigid rules, and hoarding. Compulsions can also be mental, such as praying, mentally counting, or repeating a word or phrase silently. For people with OCD there is no pleasure in doing these acts; there is only shortlived relief from the upsetting thoughts (for example, that their hands are contaminated, the house will catch on fire, or a thief will come in the door). Most people have a few repetitive habits. The difference between a harmless ritual or superstition and obsessive-compulsive disorder is that, with OCD, the thoughts and behaviors disrupt the lives of people with the disorder. People with OCD are aware that their thoughts and actions make little sense and are abnormal, but they cannot control their obsessions and compulsions.

What Causes Obsessive-Compulsive Disorder?

Scientists do not know exactly why some people develop OCD. About 2.5 percent of people in the United States are affected by OCD. All races and ethnicities have about the same rate of OCD, although the type of obsessions and compulsions vary by culture.

OCD usually begins between the ages of 10 and 24 years. It affects men and women equally, although it usually shows up at an earlier age in men. In the past, it was believed that OCD was due mainly to family problems or attitudes learned as children. As of 2016, researchers had concluded that family life has no effect on the development of the disorder. Rather, it appears that people with OCD have abnormalities in the neurotransmitters * serotonin * and dopamine * in the brain. In addition, brain imaging studies have shown that people with OCD have patterns of brain activity that differ from the patterns of people with other mental disorders and of people with no disorders at all. Twin studies strongly suggest that the tendency to develop OCD is partially due to an individual's genetic inheritance.

OCD occurs more often than average in people with certain other conditions that affect the brain and nervous system. For example, there is an increased risk of OCD in people with Tourette (tu-RET) syndrome, an inherited nervous system disorder that causes repeated, uncontrollable muscle twitches and verbal outbursts.

What Are the Symptoms of Obsessive-Compulsive Disorder?

The major sign of obsessive-compulsive disorder is an intrusive thought that creates constant worry and fear that the person tries to hold in check with a repeated behavior or compulsion. Many people who do not experience OCD believe that the worry is silly or strange. People with OCD can agree that the worry is needless; however, they cannot stop feeling the worry that comes with the thought. Obsessions and compulsions may or may not be related to each other. The thought “I might get sick” could be followed by the behavior of counting to seven rather than repeated hand washing.

Compulsions often include a wide variety of checking rituals, such as returning often to check if a door is locked, even though each time the person finds that it is. Another common compulsion is the need to precisely order or arrange certain objects, such as stuffed animals or action figures, or to count certain objects. Some people with obsessive-compulsive disorder have violent thoughts. They may fear that they or someone they love will die in a horrible accident or that they will harm someone. For example, a driver with OCD may fear that he or she has run over someone and return to the spot repeatedly to check that no one has been harmed.

How Is Obsessive-Compulsive Disorder Treated?

OCD is a mental health disorder that is diagnosed by a psychiatrist (sy-KY-uh-trist). The disorder can be present alone or with other mental health disorders. Diagnosis involves a patient history, looking for signs and symptoms, and ruling out other physical and mental conditions, including anxiety disorders, which are a group of conditions that cause people to feel extreme fear or worry that is sometimes accompanied by symptoms such as dizziness, chest pain, or difficulty sleeping or concentrating.


Studies have shown that some drugs that affect serotonin levels in the brain can reduce the symptoms of OCD. These drugs are called selective serotonin reuptake inhibitors * , or SSRIs. SSRIs help control OCD in about half of all patients, but the behaviors often return once people stop taking the drugs. For this reason, doctors often recommend a combination of prescription drugs and visits to a behavioral therapist. Some individuals with mild OCD may benefit from behavioral therapy alone.

Behavioral therapy

Research has shown that this approach can be effective for treating OCD. People who remain in therapy may gradually learn to worry less about their obsessive thoughts, and eventually they may learn to go for long periods without falling back on their compulsive actions. Overall using a combination of medication and behavioral therapy, about 70 percent of people with OCD see significant improvement in their symptoms. There is no cure for OCD, and most people receiving treatment go through periods where their symptoms get better and then get worse.

See Also: Anxiety and Anxiety Disorders: Overview • Fears and Phobias • Tourette Syndrome


Books and Articles

Brander, G. et al. “Systematic Review of Environmental Risk Factors for Obsessive-Compulsive Disorder: A Proposed Roadmap from Association to Causation.” Neuroscience and Behavioral Reviews. March 21, 2016. http://www.sciencedirect.com/science/article/pii/S0149763415302293 (accessed June 13, 2016.)

Hershfield, John. When a Family Member Has OCD. Oakland, CA: New Harbinger Pubs., 2015.

Hershfield, John, Tom Corboy, and James Claiborn. The Mindfulness Workbook for OCD: A Guide to Overcoming Obsessions and Compulsions Using Mindfulness and Cognitive Behavioral Therapy. Oakland, CA: New Harbinger Pubs., 2013.


Mayo Clinic Staff. “Obsessive-Compulsive Disorder.” Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/diseases-conditions/ocd/basics/definition/CON-20027827 (accessed March 28, 2016).

MedlinePlus. “Obsessive-Compulsive Disorder.” U.S. National Library of Medicine. https://www.nlm.nih.gov/medlineplus/obsessivecompulsivedisorder.html (accessed March 28, 2016).


American Psychiatric Association. 1000 Wilson Boulevard, Suite 1825, Arlington, VA 22209-3901. Telephone: 703-907-7300; toll-free 888-357-7924. Website: http://www.psych.org (accessed March 28, 2016).

International OCD Foundation. PO Box 961029, Boston, MA 02196. Telephone: 617-973-5801. Website: https://iocdf.org (accessed March 28, 2016).

National Institute of Mental Health. 6001 Executive Blvd., Room 6200, MSC 9663, Bethesda, MD 20892-9662. Toll-free: 866-615-6464. Website: http://www.nimh.nih.gov (accessed March 22, 2016).

* DSM-5 is the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, published by the American Psychiatric Association. This book is used by physicians in the United States to classify and diagnosis of mental conditions.

* neurotransmitters are a group of chemicals secreted by nerve cells (neurons) to carry chemical messages to other nerve cells, often as a way of transmitting nerve impulses.

* serotonin (ser-o-TOE-nin) is a substance that occurs throughout the body with numerous effects including neurotransmission. Low serotonin levels are associated with mood disorders, particularly depression and obsessive-compulsive disorder.

* dopamine (DOPE-ah-meen) is a chemical made in the brain that is involved in many brain activities, including movement and emotion.

* selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants that work by blocking the reabsorption of serotonin in brain cells, raising the level of the chemical in the brain. SSRIs include Prozac, Zoloft, Luvox, and Paxil.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)