Obsessive-compulsive disorder (OCD) is an anxiety disorder. It is a condition that can last throughout a person's life. People with OCD can become trapped in a pattern of repetitive thoughts and behaviours that are senseless and distressing, but extremely difficult to overcome.

Obsessive-compulsive disorder involves anxious thoughts (obsessions) or rituals (compulsions) which you feel you can't control. People with OCD are often plagued by persistent, unwelcome thoughts or images, or by the urgent need to engage in certain rituals.

For example, a person with OCD might be obsessed with germs or dirt, and wash his or her hands over and over. Another person may check things repeatedly or be preoccupied by thoughts of violence and fear. Obsessive counting is often seen in people with OCD.

OCD symptoms usually begin in the teenage years or early adulthood, but some children develop the illness at earlier ages, even in the pre school years. At least one-third of adults with OCD first developed the disease in childhood.

OCD tends to last for years, even decades. The symptoms may become less severe from time to time, and there may be long intervals when the symptoms are mild, but for most individuals, the symptoms are chronic.

Some people with OCD may also suffer from depression, eating disorders, substance abuse, attention deficit hyperactivity disorder (ADHD), or other anxiety disorders. When a person has other disorders, OCD is often more difficult to diagnose and treat.

Symptoms of OCD are also seen in other brain disorders, such as Tourette's syndrome. Correct diagnosisand treatment of these disorders is important for successful treatment of OCD.