Definition of Obsessive-compulsive disorder:

Obsessive-compulsive disorder is an anxiety disorder in which people have unwanted and repeated thoughts, feelings, ideas, sensations (obsessions), or behaviors that make them feel driven to do something (compulsions).

Often the person carries out the behaviors to get rid of the obsessive thoughts, but this only provides temporary relief. Not performing the obsessive rituals can cause great anxiety.

Causes, incidence, and risk factors:

Obsessive-compulsive disorder (OCD) is more common than was once thought. Most people who develop it show symptoms by age 30.

There are several theories about the cause of OCD, but none have been confirmed. Some reports have linked OCD to head injury and infections. Several studies have shown that there are brain abnormalities in patients with OCD, but more research is needed.

About 20% of people with OCD have tics, which suggests the condition may be related to Tourette syndrome. However, this link is not clear.