Munchausen syndrome is a factitious disorder, a mental disorder in which a person repeatedly and deliberately acts as if he or she has a physical or mental illness when he or she is not really sick. Munchausen syndrome is considered a mental illness because it is associated with severe emotional difficulties.

Munchausen syndrome, named for Baron von Munchausen, an 18th century German officer who was known for embellishing the stories of his life and experiences, is the most severe type of factitious disorder. Most of the symptoms in people with Munchausen syndrome are related to physical illness -- symptoms such as chest pain, stomach problems, or fever -- rather than those of a mental disorder.

NOTE: Although Munchausen syndrome usually refers to a factitious disorder with mostly physical symptoms, the term is sometimes used to refer to factitious disorders in general. In this article, Munchausen syndrome refers to the type of factitious disorder with mostly physical symptoms.