A new study found that even when men and women express the same levels of physical pain, both male and female adults are more likely to consider women's pain to be less intense than men's, displaying a significant gender bias in pain estimation that could be causing disparities in health care treatment.
In a paper published in the Journal of Pain on March 5, researchers studied the impact of a patient's gender on pain perception and treatment recommendations from a sample of average adults. They found that both male and female "perceivers" in the sample showed a reasonably strong gender bias in their assumptions of the patients' pain, which were influenced by pain-related gender stereotypes.
Tor Wager, a neuroscience professor at Dartmouth College and co-author of the paper, told The Academic Times that it's natural for there to be bias in the estimation of someone else's physical pain, because pain is subjective and complex to express. Clinicians make judgments of their patients' pain every day, and those judgments are often biased, he said. Although natural, such biases contribute to health disparities and inequity in health care.
The authors cited previous studies that found that when it comes to physical pain, health care providers are more likely to recommend psychological treatment to women than to men, and more likely to recommend pain medication to men than to women. Research has also shown that women wait longer to receive pain medication and are less likely to receive opioids for pain relief.
"Women's pain is often discounted clinically. This study is a laboratory experiment to test whether people discount women's pain in a controlled setting," Wager said. "For that, you have to have a data set that is real clinical pain, and you have to know what the ground truth for that person is. You have to control for the actual pain and for a person's level of expressiveness, which we were able to do in this study."
Much research has been done on perceived sex and gender biases in pain assessment and treatment in clinical settings, but this has not been widely studied with samples of people outside the health care industry. For the current study, the researchers ran two experiments to investigate pain estimations in average adults, because everyday pain complaints usually take place in home settings or community chronic pain programs, they said.
The first experiment involved 50 people from Boulder, Colorado, who were asked to watch video clips of men and women experiencing chronic shoulder pain, and to estimate the patients' pain intensity based on their facial expressions and physical reactions. The patients in the videos were represented by three clips each, at low, medium and high pain intensity levels. The video clips came from a database of shoulder pain patients.
Perceivers rated how much pain they thought the patients were experiencing using a scale of 0-100, ranging from "absolutely no pain" to "worst pain possible." Overall, the female patients were perceived to be in less pain than male patients at the same intensity level of pain expressiveness. And, as the researchers hypothesized, the more facially expressive the patients were, the higher the perceiver estimated their pain.
There also was no significant difference between how the male and female perceivers rated the patients' pain in the videos; across the sample, the perceivers underestimated the level of the women's pain.
"Our perceivers rated genuine pain expressions in clinical shoulder pain patients," the authors said in the paper. "Thus, the gender biases observed in the present study may be more similar to those seen in real-world clinical and lay pain evaluation contexts than in some previous studies."
The second experiment was conducted online with the objective of replicating the gender bias findings from the first experiment in a larger sample of 197 adults. The participants watched the videos of patients experiencing shoulder pain, and rated their pain on the same 0-100 scale.
But the online group of perceivers were also asked to prescribe treatments for each patient as if they were doctors. The participants were asked what dose of pain medication they would prescribe to each patient, how many sessions of psychotherapy they would prescribe and whether they thought pain medication or psychotherapy would help each patient more.
The perceivers prescribed pain medicine to women 58% of the time and psychotherapy 42% of the time, while men were prescribed pain medicine 62% of the time and psychotherapy 38% of the time.
Survey results skewed toward prescribing more psychotherapy for women and more pain medicine for men, and the authors said this can be explained by gender stereotypes. People may be thinking that women are more facially expressive and that pain causes them to wince more easily. Or they may assume that a woman's underlying pain is less intense than a man's, because they assume men are more stoic in their facial expressions.
"Generally, boys are discouraged from expressing emotions, whereas girls are permitted to express them," the authors said. "As a result, men may be more reluctant to express pain and other vulnerabilities than women. Thus, masculine gender norms are associated with high pain tolerance and stoicism whereas feminine gender norms are more permissive of expressing pain."
If women are thought to be over-emotional or exaggerating their pain, their health concerns may be discounted as not physiologically real. Wager noted, "The results were pretty clear in both studies that people underestimated pain in women compared to men, even when you account for the expression levels. The effect isn't driven by how much pain they're expressing — women aren't necessarily more expressive."
In the second experiment, the perceivers also completed the Gender Role Expectation of Pain Questionnaire, which measures gender-related stereotypical attributions about sensitivity to pain, endurance of pain and willingness to report pain. From this, the researchers found that female perceivers believed that women have higher pain endurance than men, and that both male and female perceivers believed women are substantially more willing to report pain than men.
After adding gender stereotypes about willingness to report pain to the model, female patients were still perceived to be in less pain than male patients. The researchers said this indicates that the average participant showed a "reasonably strong gender bias," and that factors such as additional pain stereotypes or perceptual biases likely contribute to this bias.
"Women are consistently found to report higher levels of pain than men and to be more expressive of pain than men," the authors said. "Perceivers may in turn get habituated to more frequent or more intense pain expressions in females and as a result reduce the pain they attribute to those expressions."
Both male and female perceivers underestimated women's pain in the study as a result of gender biases, which may be an obstacle to effective pain care. Further research on experimental approaches to characterizing biases could help develop interventions to correct them, the authors said, with implications in both clinical practice and education.
The study, "Gender biases in estimation of others' pain," published March 5 in the Journal of Pain, was authored by Lanlan Zhang, Guangzhou Sport University; Elizabeth A. Reynolds Losin, University of Miami; Yoni K. Ashar, Weill Cornell Medical College; Leonie Koban, Paris Brain Institute; and Tor D. Wager, Dartmouth College.