Obsessive-compulsive disorder (OCD) is a mental disorder most commonly characterized by intrusive, repetitive thoughts resulting in compulsive behaviors and mental acts that the person feels driven to perform, according to rules that must be applied rigidly, aimed at preventing some imagined dreaded event; however, these behaviors or mental acts are not connected to the imagined dreaded event.
In the United States, 1 in 50 adults have OCD[citation needed]. In severe cases, it affects a person's ability to function in every day activities. The disorder is often debilitating to the sufferer's (and their spouses)quality of life. Also, the psychological self-awareness of the irrationality of the disorder can be painful. For people with severe OCD, it may take several hours a day to carry out the compulsive acts.
Experts[who?] believe OCD may be related to levels of a normal chemical in the brain called serotonin. When the proper flow of serotonin is blocked, the brain's "alarm system" overreacts. Danger messages are mistakenly triggered. Instead of the brain filtering out these unnecessary thoughts, the brain dwells on them—and the person repeatedly experiences unrealistic fears and doubts.
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.[1] Although these signs are often present in OCD, a person who exhibits them does not necessarily have OCD, and may instead have obsessive-compulsive personality disorder (OCPD) or some other condition.