The molecular epidemiology of pain: a new discipline for drug discovery.

Recent candidate gene studies have identified and replicated the first associations between several common polymorphisms and pain severity in humans. Moreover, human studies in twins suggest high heritability for responses to experimental pain stimuli. Human genome-wide association studies of pain phenotypes might identify novel analgesic targets, help to prioritize research among current targets, and increase the likelihood of success for analgesic candidates emerging from animal studies. However, clinical research in pain has largely focused on small neurophysiology-based studies, so expansion of epidemiological understanding will be essential to the success of genetic or proteomic dissection of complex pain disorders. This Perspective outlines how methods of molecular epidemiology, proved effective in the study of other diseases, can enhance the returns from human genomic studies and expedite the development of new drugs to prevent or treat pain.