What Is OCD? Obsessive-Compulsive Disorder Definition

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What is obsessive-compulsive disorder or OCD? OCD is a disorder of the brain that adversely affects behavior and causes intense anxiety in those with the condition. People with the disorder experience obsessions that upset them. They may feel the urge to repeat certain rituals in an effort to control the obsessive thoughts. Experts refer to these rituals as compulsions. (Learn how OCD obsessions and compulsions make life difficult) For many, OCD begins in early childhood or adolescent years, but almost all people receive a OCD diagnosis by age 19.

Definition of Obsessive-Compulsive Disorder

Perhaps the best way to convey a true definition of obsessive-compulsive disorder involves describing what it feels like:

Imagine your mind getting stuck on a certain image or thought. Now imagine that this image or thought plays in your mind over and over and over again. No matter what you do, it still keeps coming. You want it to stop, but it simply will not.

It feels like a devastating landslide or avalanche. You begin to experience feelings of severe anxiety. Ideally, anxiety acts as your brain's warning system, alerting you about danger. The anxiety emotion tells you to react and do something to protect yourself. You may realize that the fear brought on by this repeating thought or image isn't reasonable, but it still feels very real and extremely intense.

You think that your brain wouldn't lie to you; that you wouldn't have these feelings if there weren't a real reason. But for those with OCD, the brain does lie and the warning system does not work properly, causing your mind to alert you to danger when none exists. You can read more about the effects of OCD here.

Thoughts and Rituals of Obsessive-Compulsive Disorder

The rituals of those with obsessive-compulsive disorder result out of an attempt to stop the obsessive thoughts associated with OCD. Everyone goes back, on occasion, to verify that they've turned off the oven, locked the car or front door. But for those with OCD, these compulsions become extremely excessive, interfering with normal life. The person may or may not realize that his or her thoughts and behaviors are excessive, but even those who realize that their behavior doesn't make sense cave into the compulsive ritual.

Common-obsessive thoughts include:

  • Fear of contamination by germs or harmful substances
  • Fear of harming others or self (i.e. accidentally starting a fire)
  • Unwanted sexual thoughts
  • Unwanted religious thoughts (i.e. sacrilegious images of Christ or blasphemous thoughts)
  • Need for symmetry or exactness (i.e. need to line up objects, such as toys or magazines on a table)
  • Unwanted urge to harm another

Common compulsions include:

  • Ritual hand washing
  • Excessive cleaning (i.e. house or office)
  • Ordering and arranging objects
  • Repetitive activities (i.e. walking in and out a door, opening and shutting a cabinet or drawer)
  • Counting
  • Hoarding
  • Mental rituals (i.e. silently repeating meaningless words to remove a disturbing image)

People with OCD can get help by visiting a mental health professional. The therapist or doctor can prescribe medical treatments and share self-help strategies to help break the cycle of unwanted thoughts and urges. We have more information on OCD help and self-help here.

article references

APA Reference
Gluck, S. (2022, January 11). What Is OCD? Obsessive-Compulsive Disorder Definition, HealthyPlace. Retrieved on 2024, July 25 from

Last Updated: January 15, 2022

Medically reviewed by Harry Croft, MD

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