Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by unreasonable thoughts and fears (obsessions) that lead you to do repetitive behaviors (compulsions). With obsessive-compulsive disorder, you may realize that your obsessions aren't reasonable, and you may try to ignore them or stop them. But that only increases your distress and anxiety. Ultimately, you feel driven to perform compulsive acts in an effort to ease your stressful feelings.
Obsessive-compulsive disorder often centers around themes, such as a fear of getting contaminated by germs. To ease your contamination fears, you may compulsively wash your hands until they're sore and chapped. Despite your efforts, thoughts of obsessive-compulsive behavior keep coming back. This leads to more ritualistic behavior — and a vicious cycle that's characteristic of obsessive-compulsive disorder.