According to the DSM-IV, obsessive-compulsive disorder (OCD) is characterized by recurrent obsessions or compulsions that are ego-dystonic and time-consuming and that interfere with normal functioning. Compulsions or compulsive behavior may result when patients engage in repetitive behavior in an attempt to reduce anxiety or cope with these obsessive thoughts. Obsessions refer to thoughts, ideas, or images which recur and are distressing or unwanted. Ref: Handbook of Neuropsychology and Aging edited by Paul David Nussbaum, 1997, Page 83.