Anxiety disorders affect some 40 million adults in the United States, according to the Anxiety and Depression Association of America. The International OCD Foundation estimates that about 2 million to 3 million adults nationwide have some form of OCD, a particular anxiety disorder characterized by a cycle of distressing obsessions and compulsions. One OCD subtype centers on contamination fears, which often spur compulsive hand-washing, disinfecting, avoiding contact with perceived contaminants, and other unhealthy coping mechanisms.