[Work capacity--a central category of practical social medicine]

Gainful employment-related performance capacity is a central but rarely considered category of practical social medicine. Its evaluation belongs to the workday routine of social physicians. Special difficulties arise if chronic pain disorders are to be evaluated, especially in chronic "nonspecific" cases, i.e. in the absence of biomedically relevant signs. Employment-related performance is conceptualised as a multidimensional construct with several latent variables. It integrates and extends the domains of "impairments" and "disabilities" of the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) of WHO. Three basic dimensions are distinguished: one comprising biomedical, the other psychological, the third function-related variables. They are specified within a multidimensional model of employment-related performance. This includes different components of the perception and appraisal of pain, concomitant bodily complaints (e.g. vital exhaustion), psychological impairments as helplessness or anxiety, special facets of the pain behaviour, and functional limitations and allows an estimate of the chronification and prognosis of the pain problem. Some diagnostic measures are still inadequate in respect of established clinimetric standards. In particular, assessment of functional limitations requires further development and research.