Individual Differences in Pain: Understanding the Mosaic that Makes Pain Personal – free full-text article /PMC5350021/
This study, in the full text (link above), contains direct quotes from interviews of the patients. It was interesting to get such a close-up look into other people’s pain.
The experience of pain is characterized by tremendous inter-individual variability.
Multiple biological and psychosocial variables contribute to these individual differences in pain, including demographic variables, genetic factors, and psychosocial processes.
Similarly, both genetic and psychosocial factors contribute to clinical and experimental pain responses. Importantly, these different biopsychosocial influences interact with each other in complex ways to sculpt the experience of pain.
The individual and combined influences of these biological and psychosocial variables results in a unique mosaic of factors that contributes pain in each individual.
Understanding these mosaics is critically important in order to provide optimal pain treatment.
Abstract above, full text below.
It has long been appreciated that individuals differ from each other in important ways. Such individual differences are a hallmark of the experience of pain and have been a topic of keen interest to pain researchers for many years.
The purpose of this article is to provide an overview of factors contributing to individual differences in pain.
First, I will introduce the topic of individual differences in responses to pain and its treatment, including a biopsychosocial context for conceptualizing individual differences.
Then, I will present findings regarding demographic factors that are associated with individual differences in pain.
Next, I will discuss genetic and psychosocial contributions to individual differences, and I will present examples of interactions among these multiple individual difference factors.
I will describe the clinical implications of individual differences in pain, followed by conclusions and recommendations for future research.
By definition pain is a subjective and highly personal experience, which presents challenges for both the researcher and clinician
direct measurement of pain is impossible, rather we must rely on individuals’ self-report, and to some extent their behavior, to provide a glimpse into their experience
However, an equally important but less often discussed challenge results from the highly personal nature of the pain experience; the experience of pain is sculpted by a mosaic of factors unique to the person, which renders the pain experience completely individualized
That is, there are pervasive and important individual differences in pain, and these individual differences produce pain experiences that are completely unique to the person experiencing them (i.e. they make the pain personal).
Perhaps the simplest manifestation of individual differences is that an experimental stimulus delivered at a standardized intensity elicits subjective pain reports that vary dramatically between individuals,
…these differences in self-reported pain are corroborated by inter-individual differences in cerebral activation evoked by the same painful stimulus
Similarly, responses to pain treatments are characterized by robust individual differences.
When considering individual difference factors, it is important to distinguish characteristics of the individual that are statistically associated with pain responses (i.e. markers) from biological and psychosocial mechanisms that directly influence pain responses.
incorporating an understanding of individual differences into assessment and diagnosis of pain in the clinical setting may allow the clinician to select treatments that are tailored to the patient, thereby improving treatment outcomes.
Demographic Influences on Pain
As noted above, demographic factors do not directly influence pain, however they represent valuable individual difference factors, because they are easily measured and they provide important public health information regarding large population groups that may be at risk for increased pain.
Here they admit that instead of tracking and treating pain, they are looking for factors that can be measured; only those can be spun into a scientific study.
That is, the prevalence of joint pain generally increases monotonically with age, and explanations for this association will enhance our mechanistic understanding of joint pain.
Given the aging of the world’s population, whether the experience of pain changes with age has drawn increasing attention in recent years
Patterns of pain prevalence across the lifespan are complex and they vary across pain conditions (see Figure 2).
- Briefly, the prevalence of joint pain, lower extremity pain and neuropathic pains tend to increase monotonically with age.
- General chronic pain increases in prevalence until middle age, at which time the prevalence plateaus.
- In contrast, pain conditions such as headache, abdominal pain, back pain and temporomandibular disorders show peak prevalence in the third to fifth decades of life, after which their frequency decreases.
Beyond pain prevalence, multiple studies have examined age-related changes in the severity and impact of pain. …age-related differences in the intensity and impact of chronic pain have not been consistently demonstrated.
Patterns of pain prevalence across the adult lifespan.
- The top panel shows that prevalence increases monotonically with age for several pain conditions, including joint pain, lower extremity pain, and neuropathic pains.
- The middle panel shows that for general chronic pain, prevalence seems to increase until middle age, at which time it plateaus.
- The bottom panel shows a pattern of increasing prevalence until middle age followed by a decrease in prevalence in later life for several conditions, including headache, abdominal pain, back pain, chest pain.
It is important to recognize that these prevalence patterns are based on cross-sectional rather than longitudinal data; therefore, one cannot deduce pain trajectories within people from these data.
Taken together these findings suggest that older adults show less sensitivity to brief, cutaneous pains (e.g. heat pain threshold); however, sensitivity to more sustained pain stimuli that impact deeper tissues increases with age.
Moreover, several studies have demonstrated increased temporal summation of pain among older adults, while conditioned pain modulation consistently has been found to decrease with age
This pattern of results suggests that aging is associated with a shift in pain modulatory balance, such that older adults show enhanced pain facilitation combined with decreased pain inhibition.
A variety of biopsychosocial factors have been posited to contribute to these age-related changes in pain processing
How is it possible that they don’t consider the consistent and eventually irreparable breakdown of aging tissues, structures, organs (which is accelerated with EDS)? Why pain increases as we age is no mystery to anyone except to these “researchers”.
First, many pain-related diseases increase in frequency with age (e.g. diabetes, osteoarthritis, many forms of cancer, neurological diseases), which can contribute to increased pain among older adults.
Moreover, many of the biological changes that underlie aging can also contribute to increased clinical pain and altered pain modulatory balance, including systemic inflammation, oxidative stress, altered autonomic function, and changes in neuronal structure and function.
We all know that aging is painful, but here’s a scientific explanation.
In addition, psychosocial changes that occur with age could also impact pain. Reductions in cognitive function, sleep quality, and social support are all common in older adults, and these factors are also associated with increased pain
Notably, undertreatment of pain in older adults is common, which could further contribute to greater pain in this population
I don’t know why this would only be true of “older adults” when all pain patients are being denied treatment to palliate their pain.
Interactions Among Biopsychosocial Factors
The biopsychosocial model does not simply propose that factors from biological, psychological and social domains exert important influences on pain. Perhaps the most important aspect of the model is its insistence that these different sets of factors interact to create the experience of pain. These interactions are depicted by the three-way bidirectional arrows in Figure 3.
Biopsychosocial model of pain.
The figure illustrates that the experience of pain is sculpted by the influences of biological, psychological and social factors.
Notably, while each of these factors can independently influence pain (as depicted by small bidirectional arrows), the more important and complex influences emerge from interactions among the factors, as depicted by the larger three-way arrows. These interactions among multiple biopsychosocial factors results in a unique mosaic of individual difference factors contributing to pain in each person.
Genetic Influences on Pain
Genetic associations with pain have been found to vary by sex and ethnic group, which reflects moderation as described above. Importantly, such interactions suggest that the biological pathways represented by the gene may differentially influence pain responses in different population groups.
The goal is to deploy personalized pain management, which is not simply pharmacotherapy based on genetic profile, rather truly personalized therapy is comprised of multiple treatment modalities designed specifically for each patient to target her or his singular mosaic.
This is a nice description of the ideal: individualized treatment plans “comprised of multiple treatment modalities designed specifically for each patient.”
The experience of pain is characterized by robust inter-individual differences.
The many variables whose individual and combined influences drive individual differences produce a mosaic that uniquely contributes to pain in each patient.
An understanding of these individual differences is critical for effective pain assessment and management, serving as the foundation for personalized pain treatment, an as yet unrealized goal.
I recommend reading the full article which has quotes from the interviews: