Disorder was used to refer to a "generic group". Specific diagnoses were referred to as "reactions". 

It conceptualizes psychopathology as a dynamic response  to various distressing circumstances, as opposed to the more biological notions in the previous manual. 

There are 10 basic diagnostic categories. 

University of Illinois at Urbana-Champaign

In 1945, shortly after WWII, issued in War Department Technical Bulletin, Medical 203, the Office of the Surgeon General released Nomenclature and Method of Recording Diagnoses. Influenced by soldiers’ experiences in WWII, this issue was designed in an attempt to move away from the traditional focus on mental institutions and clinical perspectives. In 1946, it was reprinted for public use in the Journal of Clinical Psychology under the title of Nomenclature of Psychiatric Disorders and Reactions (known as Medical 203).

Medical 203

Clegg, J. W. (2012). Teaching about mental health and illness through the history of the DSM. History of psychology, 15(4), 364. https://doi.org/10.1037/a0027249

Teaching about mental health and illness through the history of the DSM

Around the time of WWII, psychodynamic therapies are found to be successful in treating war-related psychological trauma.

Clinicians became dissatisfied with the previously biological oriented, symptom-based classification. The Medical 203 adopted a new way of classifying psychopathology. 

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