I had one case of this where we ruled out every stinking thing possible and it was finally labeled maniac depression with no biological explanation.
Hypochondriasis (or hypochondria, often referred to as health phobia or health anxiety) refers to an excessive preoccupation or worry about having a serious illness.[1] Often, hypochondria persists even after a physician has evaluated a person and reassured them that their concerns about symptoms do not have an underlying medical basis or, if there is a medical illness, the concerns are far in excess of what is appropriate for the level of disease. Many people suffering from this disorder focus on a particular symptom as the catalyst of their worrying, such as gastro-intestinal problems, palpitations, or muscle fatigue.
The DSM-IV-TR defines this disorder, "Hypochondriasis," as a somatoform disorder[2] and one study has shown it to affect about 3% of the visitors to primary care settings.[3]
Hypochondria is often characterized by fears that minor bodily symptoms may indicate a serious illness, constant self-examination and self-diagnosis, and a preoccupation with one's body. Many individuals with hypochondriasis express doubt and disbelief in the doctors' diagnosis, and report that doctors’ reassurance about an absence of a serious medical condition is unconvincing, or un-lasting. Many hypochondriacs require constant reassurance, either from doctors, family, or friends, and the disorder can become a disabling torment for the individual with hypochondriasis, as well as his or her family and friends. Some hypochondriacal individuals are completely avoidant of any reminder of illness, whereas others are frequent visitors of doctors’ offices. Other hypochondriacs will never speak about their terror, convinced that their fear of having a serious illness will not be taken seriously by those in whom they confide.