U.K. neurologist Dr. Suzanne O'Sullivan has spent her life treating psychosomatic illnesses, or disorders in which people suffer from debilitating physical symptoms that cannot be explained by a physical examination or medical investigation.
Psychosomatic illnesses may overlap with what are termed "functional disorders," though the latter may not have any psychological component. One example of psychosomatic illness are psychogenic nonepileptic seizures, in which a person experiences seizure-like attacks without the telltale explosion of electrical activity seen in the brains of people with epileptic seizures.
