People with obsessive-compulsive disorder (OCD), a form of anxiety disorder, suffer intensely from unwanted recurring thoughts (obsessions) or rituals (compulsions), which they feel they cannot control. Rituals such as counting, washing, or cleaning are often performed with the hope of preventing obsessive thoughts or making them go away. Performing these rituals provides only temporary relief; not performing them markedly increases anxiety. Left untreated, obsessions and the need to perform rituals can take over a person’s life.

Although a lot of healthy people can relate to some of the symptoms of OCD, such as checking the stove or whether the coffeepot is plugged in before leaving the house, the disorder is diagnosed only when such activities consume at least an hour a day, are very distressing, and interfere with daily life.

About 1.2% of the U.S. population has OCD in any given year, with women affected at a slightly higher rate than men. While the disorder usually begins during adolescence or early childhood, recent research shows that some children develop the illness even earlier, during the preschool years.