A somatic delusion is a false belief that a body function or part is diseased, malformed, or functioning improperly. Somatic means related to the body and delusions and are false beliefs or impressions that are held even when rationality is challenged or contradictory evidence is presented. Somatic delusions are therefore false beliefs regarding the body and its processes that are held even when contradicting information is presented. Often times somatic delusions are extreme. Examples include the belief that the organs are rotting on the inside or infested with worms or bugs. A person may believe they are suffering from a rare and deadly disease even when tests are conducted that prove that isn't a possibility.