Somatoform disorders and recent diagnostic controversies.

Classification is not a trivial matter. In Burmese Days, George Orwell writes, "It is devilish to suffer from a pain that is all but nameless. Blessed are they who are stricken only with classifiable diseases! Blessed are the poor, the sick, the crossed in love, for at least other people know what is the matter with them and will listen to their belly-achings with sympathy." Patients who have somatoform disorders are particularly susceptible to this Orwellian lamentation. They are afflicted by symptoms that defy simple explanations. As detailed in this article, there is a spectrum of medical and psychiatric factors that can cause or contribute to somatic symptom burden. Research is continuing to reveal the central mechanisms that may provide a common pathway for physical and psychologic symptoms. The dualism that places some somatic symptom disorders on Axis I and others on Axis III gradually may fade in the coming decades as what the unifying causes are among common symptoms and the multicausal nature of many symptoms are discovered. Meanwhile, the classification systems should continue to operate on pragmatic principles where mechanistic explanations are lacking. This will allow grouping patients into categories that inform research, scientific and patient communication, prognostication, and clinical management. Coupling a heuristic classification system with evidence-based measures for assessing severity and monitoring treatment outcomes are important steps in the optimal care of symptomatic patients.