[Chronic pain: introduction].

This paper is an introduction to a teaching session devoted to chronic pain. The results of a belgian epidemiological study illustrate the social and economical consequences of acute and chronic pain. Many studies have revealed that, if we want to understand the onset and the perpetuating mechanisms of chronic pain, we have to take into account a conjunction of biological, psychological and social factors. The general practitioner should be aware of this biopsychosocial model, the main points of which being summarised in this introduction. The teaching staff will deal with chronic headaches, psychoanalytical approach to chronic pain, and the so-called "invasive" techniques of pain control.