Subtype refers to a Group of people with a specific disorder who have something in common, such as symptoms, etiology, problem severity, or likely outcome, that makes them distinct f
rom people with other subtypes of the same disorder.
Other /More definition:
subtype refers to a group of people with a specific disorder who have something in common, such as symptoms, etiology, problem severity, or likely outcome, that makes them distinct from people with other subtypes of the same disorder.
Lexicon of Psychology - Terms, Treatments, Biographies,