The Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, is the handbook used most often in diagnosing mental disorders in the United States.
While widely accepted among psychologists and psychiatrists, the manual has proved controversial in its listing of certain characteristics as mental disorders. The most notorious example is the listing in the DSM-II of homosexuality as a mental disorder; a classification that was removed by vote of the APA in 1973.
The early DSM's distinguished between a psychosis and a neurosis. A psychosis is a severe mental disorder characterized by a break with reality. Psychoses typically involve hallucinations, delusions, and illogical thinking. A neurosis is a milder mental disorder characterized by distortions of reality, but not a complete break with reality. Neuroses typically involve anxiety and depression.
Brief history of DSM
Both of these editions were strongly influenced by the psychodynamic approach. There was no sharp distinction between normal and abnormal, and all disorders were considered reactions to environmental events. Mental disorders existed on a continuum of behavior. This way, everyone is more or less abnormal. The people with more severe abnormalities have more severe difficulties with functioning.
See also: International Statistical Classification of Diseases and Related Health Problems, personality disorder