A mental disorder characterized by an excessive and habitual preoccupation with personal health and a tendency to interpret insignificant or imaginary conditions as evidence of serious disease; also called hypochondriasis.
Typically, hypochondriacs not only falsely believe that they have a serious disease (often, but not exclusively, of the heart or another internal organ), they persist in this belief even after being assured that they do not have the disease by a physician (or, usually, by many physicians). Hypochondriacs seem to have an increased sensitivity to internal sensations. It is also thought that serious childhood illness or experience with disease in a family member or friend may be associated with hypochondria, and that psychological stress in early adulthood related to disease or death may precipitate or worsen this condition.
Baur, Susan. Hypochondria. Berkeley: University of California Press, 1988.