Media Releases

University of Toronto psychologists identify influence of human social interaction on sensitivity to physical pain

November 8, 2010

TORONTO, ON – Psy­chol­o­gists at the Uni­ver­si­ty of Toron­to have shown that the nature of a social inter­ac­tion has the abil­i­ty to influ­ence an individual’s sen­si­tiv­i­ty to phys­i­cal pain.  The dis­cov­ery could have sig­nif­i­cant clin­i­cal impli­ca­tions for doc­tor-patient rela­tion­ships and the gen­er­al well-being of an indi­vid­ual on a dai­ly basis.

“Dozens of stud­ies over the past sev­er­al decades have demon­strat­ed the impact of inad­e­quate social con­nect­ed­ness on numer­ous health out­comes, includ­ing car­dio­vas­cu­lar health, immune func­tion, post-sur­gi­cal recov­ery, and lifes­pan,” says Ter­ry Bor­sook, a PhD stu­dent in the Depart­ment of Psy­chol­o­gy at U of T and author of a new study pub­lished in PAIN.  “Our study is among the first to show in humans that the per­cep­tion of phys­i­cal pain can be imme­di­ate­ly impact­ed by the types of social expe­ri­ences that peo­ple have in their every­day lives.”

In the study, healthy par­tic­i­pants rat­ed the inten­si­ty and unpleas­ant­ness of painful stim­uli before and after engag­ing in a struc­tured inter­ac­tion with a trained actor who was instruct­ed to be either warm and friend­ly or indif­fer­ent through­out the exchange.  Par­tic­i­pants who expe­ri­enced the indif­fer­ent social exchange report­ed less sen­si­tiv­i­ty to pain after the inter­ac­tion when com­pared to that mea­sured before the exchange.  Par­tic­i­pants exposed to the pos­i­tive social inter­ac­tion, how­ev­er, exhib­it­ed no change in pain sen­si­tiv­i­ty.

“While the anal­gesic effect result­ing from a social­ly dis­con­nect­ing event might seem like a good thing, we know from a great deal of research in ani­mals and humans that social threats pro­voke the well-known fight-or-flight stress response, of which pain inhi­bi­tion is a typ­i­cal com­po­nent.”

Bor­sook says that the results sug­gest that social rela­tion­ships may be of such crit­i­cal impor­tance to human health and well-being that even a mild threat of dis­con­nec­tion can be stress­ful.

“This stress-induced anal­ge­sia evolved so that we can escape threats with­out being hob­bled by pain.  The pain reduc­tion observed in our study is thus con­sis­tent with pri­or find­ings but what is remark­able about our results is that anal­ge­sia occurred in response to a type of expe­ri­ence that peo­ple expe­ri­ence in dai­ly life, per­haps sev­er­al times a day,” says Bor­sook.  “If such every­day mild­ly unpleas­ant encoun­ters are enough to pro­voke pain inhi­bi­tion, then this sug­gests that many peo­ple may be exposed to chron­ic fight-or-flight respons­es, which can have many neg­a­tive impli­ca­tions for health.  This would be the case espe­cial­ly for peo­ple who are sen­si­tive to social exclu­sion, such as those who feel lone­ly or fear rejec­tion”

Bor­sook says that the results also have impor­tant clin­i­cal impli­ca­tions when it comes to see­ing your doc­tor.  “Health prac­ti­tion­ers who are aloof, lack under­stand­ing, or are gen­er­al­ly unre­spon­sive to patients may pro­voke an anal­gesic response result­ing in under­es­ti­mat­ed reports of pain, with insuf­fi­cient pain con­trol mea­sures being a pos­si­ble con­se­quence.”

The find­ings are pre­sent­ed in a paper titled “Mild­ly neg­a­tive social encoun­ters reduce phys­i­cal pain sen­si­tiv­i­ty”, pub­lished in the Novem­ber issue of PAIN, the offi­cial pub­li­ca­tion of the Inter­na­tion­al Asso­ci­a­tion for the Study of Pain.

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For more infor­ma­tion, please con­tact:

Ter­ry Bor­sook
Depart­ment of Psy­chol­o­gy
Uni­ver­si­ty of Toron­to

Sean Bet­tam
Com­mu­ni­ca­tions, Fac­ul­ty of Arts & Sci­ence
Uni­ver­si­ty of Toron­to