The role of situational variables in pain control.

The understanding of human pain perception, nociceptive systems, and analgesia is complicated by the variety of psychological, social and contextual variables that may interact with noxious sensory input to produce inexplicable changes in the strength, unpleasantness or quality of pain that is experienced. Consequently, many clinical and experimental studies aim to elucidate the mechanism by which psychological variables affect both neural coding and the resulting pain perception. Recently, more attention has focused on situational variables as important modifiers of pain and analgesic efficacy. Situational variables refer to the specific combination of psychological and contextual factors that exist in a particular pain situation. These variables represent a unique interaction between the individual experiencing pain and the context in which the pain is experienced.This article reviews the role of situational variables for modifying multiple dimensions of pain perception. Observations from human and animal research studies have been integrated to illustrate the potential of situational variables for enhancing or for reducing pain that is produced by a noxious stimulus. Clinical and experimental research designs are presented which may be used to identify relevant situational variables, to determine their effect on pain perception, to assess their interaction with analgesic efficacy, and to evaluate their mechanisms of action.