DISORDERS CHARACTERIZED BY PAIN - A METHODOLOGICAL REVIEW OF POPULATION SURVEYS

Objective - To review a series of conceptual and methodological proble ms encountered in surveys primarily devoted to pain disorders. Criteri a for inclusion and exclusion of articles - Published reports were sys tematically collected by electronic database searches (Medline), citat ions in existing publications, and through personal contacts. Relevant articles from clinical and epidemiological research on pain were incl uded and special attention was given to epidemiological research on ba ck pain. Conclusions - Surveys of pain disorders should be based on a multidimensional pain model that includes nociceptive input, pain perc eption, suffering, and pain behaviour as major components. Because of the limited applicability of diagnostic procedures or genuine ''non-sp ecificity'' of pain states, or both, epidemiological surveys may resul t in a considerable proportion of cases without an identifiable pathop hysiological basis. Staging and grading procedures for pain disorders (as distinguished from classification) may comprise various aspects of pain perception: regional distribution, pain intensity, temporal char acteristics, sensory qualities, and dimensions of cognitive-emotional appraisal. Description of temporal development and chronification (sta ging) should refer to different components of the multidimensional pai n model. Explicit a posteriori procedures for grading are preferable t o implicit grading based on question wording. Evidence from several so urces suggests that localistic concepts of pain may be misleading. Ide ntification of complex pain syndromes should be one primary target for epidemiological pain surveys. Of the many factors that may impair the reliability and validity of data collected in pain surveys, recall bi ases seem to deserve special attention.