The DSM-IV is the fourth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM is a manual written by the American Psychiatric Association (APA). They are numbered using Roman numerals: DSM-I, DSM-II, DSM-III, DSM-IV, but the latest edition adopted Arabic numerals allowing subsequent editions to be numbered, 5.1, 5.2 and so on. After the DSM-IV was published, some changes (or revisions) were made to the descriptions in the manual. Because of this, the most recent version of the DSM-IV is officially called the DSM-IV-TR (the TR stands for "Text Revision").