DSM stands for Diagnostic and Statistical Manual of Mental Disorders and is published by the American Psychiatric Association, the professional membership organization representing psychiatrists in the United States. It is used by mental health professionals from a variety of disciplines and backgrounds for a wide range of purposes, including clinical, research, administrative and educational.
The DSM contains a listing of psychiatric disorders and their corresponding diagnostic codes. Each disorder included in the manual is accompanied by a set of diagnostic criteria and text containing information about the disorder, such as associated features; prevalence; familial patterns; age-, culture- and gender-specific features; and differential diagnosis.
Diagnostic criteria have been included in the DSM because their provision has been shown to increase diagnostic agreement. It is important to understand that the appropriate use of the diagnostic criteria requires clinical training and that they cannot be simply applied in a cookbook fashion.
Just because a category is not included in DSM-IV does not necessarily mean that it is invalid or not worthy of being a focus of research or treatment.
There are many ways diagnoses have ended up in the DSM. During the time of the publication of DSM-I and DSM-II (1952 and 1968, respectively), there was very little empirical data available about psychiatric disorders.
Starting [in 1980] with DSM-III, with the explosion of research in psychiatry, attempts have been made to make the DSM as empirically based as possible. [This is when autism was included in the DSM.]
The most recent major revision was DSM-IV, published in 1994. The next edition, DSM-V, is not scheduled for publication until 2012.