ABSTRACT
This chapter outlines the parts of the nervous system involved in the sensation of pain, and describes those properties of the system which may cause changes in function and thereby cause long-lasting or chronic pain states. There is much evidence of an association between workload and chronic musculoskeletal pain. The observation that patients suffering from chronic pain tend to respond with a much larger increase in pain during work than healthy persons suggests that there is no adaptation. The modulation of long-lasting pain and the mechanisms of development of chronic pain are considerably less known than the modulation of acute pain. The biomedical approach to chronic non-malignant pain proved ultimately to be fruitless. Chronic pain patients commonly report that the pain increases when they are in large gatherings or are stressed, and diminishes when they are enjoying themselves or absorbed in meaningful activity.
