obsessive-compulsive disorder

n. A disorder characterized by (1) recurrent and persistent thoughts, images, ideas, or impulses that cause the person distress and seem intrusive and inappropriate and are beyond one's will to stop; they are often quite frustrating as they seem alien to the self, and yet the person is unable to prevent or stop the thought process involved. It is also characterized by (2) repetitive behaviors such as hand washing, checking things, or mental acts the person feels compelled to perform in response to an obsession and often with rigid rules intended to ward off distress or the occurrence of some dreaded event.