Obsessive–compulsive disorder (OCD) is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing anxiety, or by a combination of such thoughts (obsessions) and behaviors (compulsions). Symptoms may include repetitive handwashing; extensive hoarding; preoccupation with sexual or aggressive impulses, or with particular religious beliefs; aversion to odd numbers; and nervous habits, such as opening a door and closing it a certain number of times before one enters or leaves a room. These symptoms can be alienating and time-consuming, and often cause severe emotional and financial distress. The acts of those who have OCD may appear paranoid and come across to others as psychotic. However, OCD sufferers generally recognize their thoughts and subsequent actions as irrational, and they may become further distressed by this realization.
OCD is the fourth-most-common mental disorder, and is diagnosed nearly as often as asthma and diabetes mellitus.In the United States, one in 50 adults has OCD. The phrase “obsessive–compulsive” has become part of the English lexicon, and is often used in an informal or caricatured manner to describe someone who is meticulous, perfectionistic, absorbed in a cause, or otherwise fixated on something or someone. Although these signs may be present in OCD, a person who exhibits them does not necessarily have OCD, and may instead have obsessive–compulsive personality disorder (OCPD), an autism spectrum disorder, or no clinical condition. Multiple psychological and biological factors may be involved in causing obsessive–compulsive syndrome