Mental health professionals and scientists must have a common language to communicate with their colleagues, with professional agencies, and with patients and the general public. The primary purpose of an official, authoritative diagnostic nomenclature is to provide this common language that minimizes the use of idiosyncratic and invalid concepts. The American Psychiatric Association’s (APA’s) Diagnostic and Statistical Manual of Mental Disorders (DSM-5) provides this common language for the description of psychopathology. DSM-5 is the current edition of the APA’s diagnostic manual.