The last 6 years has seen many advances in our knowledge of illnesses. The DSM-IV-TRV spans the bridge between DSM- IVV and DSM-VV to ensur e that the most relevant new information since the DSM- IVV literature review in 1992 was incorporated and to enhance the educational value. Specifically, new information on associated features, including associated laboratory and physical findings, has been added for many of th e disorders. Sections on prevalence, gender/age/culture, course, and familial pattern have also been revised to reflect recent research fin dings. More comprehensive differential diagnoses have been incorporat ed for many of the disorders.