Individual differences in pain responses.

The experience of pain is characterized by tremendous inter-individual variability. Indeed, an identical noxious stimulus can produce vastly different pain responses across individuals. Historically, scientists have regarded this variability as a nuisance; however, substantial data suggest that these individual differences may provide valuable information that can be used to enhance clinical management of pain. This paper discusses several factors that contribute to individual differences in pain perception, including demographic (ie, sex, age, and ethnicity), genetic, and psychosocial variables. These factors are discussed in the context of the biopsychosocial model of pain, which posits that pain perception is influenced by interactions among biologic, psychosocial, and sociocultural factors. Finally, the clinical and scientific implications of individual differences in pain are discussed.