Flooding is a form of exposure therapy that is often used with adults who have posttraumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), phobic disorders, and other anxiety [Page 656]disorders. Flooding is characterized by engaging the client with her most feared situation for an extended period of time in order to reduce her fear response as efficiently and quickly as possible. The actual administration of flooding as an exposure methodology often takes on a variety of forms, and its theoretical underpinnings allow it to serve as an effective treatment for a variety of clinical presentations. This entry discusses the theoretical framework behind flooding, as well as its application in treating certain disorders.