Obsessive-compulsive disorder OCD

Obsessive-compulsive disorder (OCD) is a mental disorder characterized by intrusive 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 reducing anxiety by preventing some imagined dreaded event; however, these compulsive behaviors and mental acts are not connected to the imagined dreaded event.

OCD is the fourth most common mental disorder and is nearly as common as asthma and diabetes mellitus. In the United States, one in 50 adults has OCD.In severe cases; it affects a person's ability to function in everyday activities. The disorder often has a serious impact on the sufferer's (and their family's) 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.

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 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.

http://en.wikipedia.org/wiki/Obsessive-compulsive_disorder