Final answer:
Roderick Usher in 'The Fall of the House of Usher' by Edgar Allan Poe, appears to suffer from a mental disorder with physical manifestations, possibly compounded by a hereditary illness due to the family's history of insular breeding.
Step-by-step explanation:
The type of disorder that Roderick Usher has in Edgar Allan Poe's short story The Fall of the House of Usher could be characterized as a mental disorder with physiological symptoms.
The descriptions throughout the text hint at a combination of acute anxiety, depression, and perhaps some form of psychosis, as illustrated by the cadaverous appearance, the nervous agitation, the exaggerated features, hysteria, and the growing insanity that the character demonstrates.
The text also alludes to the possibility of hereditary illness, augmented by the family's insular breeding, which may have intensified any congenital ailments.
The disorder that Roderick Usher is believed to have is not explicitly stated in the text. However, based on the symptoms and descriptions provided, it is possible to infer that he may suffer from a combination of mental disorders such as anxiety, depression, and possibly schizophrenia.