How are obsessions and compulsions connected in obsessive-compulsive disorder?

In obsessive-compulsive disorder (OCD), obsessions and compulsions are closely linked, though they can occur independently. Obsessions are persistent, involuntary thoughts, images, or impulses that trigger significant anxiety. Compulsions are repetitive, ritualistic acts that a person feels driven to perform to relieve that mounting anxiety, even when they recognize the act as meaningless.1

In approximately 80 percent of cases, these two symptoms appear in sequence. The relationship is functional: the individual performs the compulsion not for its own sake, but as a mechanism to prevent a feared situation or to alleviate the distress caused by the intrusive obsessive thoughts. If a person is prevented from completing these rituals, the resulting anxiety can become overwhelming. While the disorder is often treated with antidepressants and behavioral therapy, the cycle of obsessions and compulsions remains a defining feature that interferes with daily functioning.123