Ecological validity of laboratory findings in healthy humans about the role of certain biopsychological factors on sex differences in pain perception needs to be assessed/improved.
This systematic review summarizes the results of 10 years of laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian to access multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The second set of results presented in this review (129 articles) examined various biopsychosocial factors that may contribute to differences in pain sensitivity between healthy women and men. The results revealed that the involvement of hormonal and physiological factors is either inconsistent or absent. Some studies suggest that temporal summation, allodynia, and secondary hyperalgesia may be more pronounced in women than in men. The evidence to support less efficient endogenous pain inhibitory systems in women is mixed and does not necessarily apply to all pain modalities. With regard to psychological factors, depression may not mediate sex differences in pain perception, while the role of anxiety is ambiguous. Cognitive and social factors appear to partly explain some sex-related differences. Finally, past individual history may be influential in female pain responses. However, these conclusions must be treated with much circumspection for various methodological reasons. Furthermore, some factors/mechanisms remain understudied in the field. There is also a need to assess and improve the ecological validity of findings from laboratory studies on healthy subjects, and perhaps a change of paradigm needs to be considered at this point in time to better understand the factors that influence the experience of women and men who suffer from acute or chronic pain.
aDepartment of Psychology, Université du Québec à Montréal, Montreal, Quebec, Canada
bCentre de recherche, Centre hospitalier de l’Université de Montréal (CRCHUM), Montreal, Quebec, Canada
cÉcole de réadaptation, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
dLife Sciences Library, McGill University, Montreal, Quebec, Canada
eDepartment of Family Medicine and Emergency, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
fResearch Centre, Montreal Heart Institute, Montreal, Quebec, Canada
gDepartment of Anaesthesiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
*Corresponding author at: Centre de recherche, Centre hospitalier de l’Université de Montréal (CRCHUM) − Hôtel-Dieu, Masson Pavilion, 3850 St. Urbain Street, Room 8-211, Montreal, QC, Canada H2W 1T7. Tel.: +1 514 890 8000x14082; fax: +1 514 412 7027.
Submitted February 15, 2011; revised November 15, 2011; accepted November 22, 2011.