Many people present with medically unexplained symptoms. For example, more than a quarter of primary care patients in England have unexplained chronic pain, irritable bowel syndrome, or chronic fatigue,1 and in secondary and tertiary care, around a third of new neurological outpatients have symptoms thought by neurologists to be “not at all” or only “somewhat” explained by disease.2 This is not a problem just in developed countries—in Bangladesh, only a third of women with abnormal vaginal discharge had evidence of infection.3 These disorders are important because they are common and they cause similar levels of disability as symptoms caused by disease.4 If not treated properly they can result in large amounts of resources being wasted5 and iatrogenic harm.

This is a clinically, conceptually, and emotionally difficult area. Clinical presentations vary greatly—from people who frequently attend the general practitioner with minor symptoms to people with chronic fatigue who are bed bound. What unites them, however, is the difficulty in explaining the presenting symptoms on the basis of any known pathology. Strong feelings are common, with patients often referred to in pejorative terms as “frequent fliers,” “heart sink patients,” “thick folder patients,” or “somatisers.” Doctors may feel that their competence is challenged by their inability to explain the symptoms, and patients may feel that they …