OCD is characterized by obsessions and/or compulsions that are distressing or time-consuming, impede normal functioning, or interfere with usual social activities or relationships. Obsessions are persistent and/or urgently recurring thoughts that the person experiences as intrusive, inappropriate, distressing, and outside of his/her control. The thoughts are about something other than real life worries.

Compulsions are repetitive behaviors or rituals that are preformed in response to obsessions or according to a rigid set of rules. Although they are performed to reduce or avoid distress or to thwart a dreaded event, they are excessive and not associated in any practical or functional way to the things they are intended to offset or prevent.

Symptoms of OCD usually first appear in adolescence or early adulthood, but may begin in childhood. Individuals with OCD typically have depressed moods as well.

Treatment usually involves behavioral therapies, including exposure and response prevention. Supportive therapy also assists with related symptoms and problems, such as depression and difficulties in familial and social relationships. There is a strong biological component; thus, medication treatment is often recommended in addition to individual therapy.