What is chronic pain?

Chronic pain leads to individual suffering and to major costs for all developed countries. Previous studies suggest that both the incidence of disabling chronic pain and the amount of health care consumption due to chronic pain are rapidly increasing. Western medicine is not only often ineffective but may be one of the causes of this epidemic. This article will address the issue of chronic pain of unknown etiology and has the goals of: (1) identifying the factors which have led to our confusion about this topic, and (2) proposing alternative ways of conceptualizing chronic pain and its ensuing behaviors and social consequences. It is concluded that it is essential to discriminate between tissue damage, pain, suffering, pain behaviors, health care consumption, impairment and disability if one is to develop a meaningful conceptualization of the medical, social, economic and political problems of chronic pain. Successful treatment must be defined in behavioral terms such as restoration of normal activities. Disabling chronic pain is often a sign of overwhelming stress engendered by the individual's failure to cope with the demands of industrialized society.     

Do pain expectancies cause pain in chronic low back patients? A clinical investigation

The present study investigated whether pain expectancies cause pain in chronic low back patients. Back patients (N = 29) were requested to perform four exercise bouts (two with each leg), each consisting of flexing and extending the knee three times at maximal force (Cybex 350 System). During each exercise bout the baseline pain, the expected pain and experienced pain were recorded. Patients also reported their experienced fear of further injury to the back. Furthermore, the peak force of both knee flexors and extensors was assessed. Although patients did expect a back pain increase during the first exercise bout with each leg, no evidence was found for the thesis that pain expectancies generate increases in subjective pain experiences. Instead, the reported pain expectancy was readily corrected during the next exercise bout, whereas the experienced pain remained unchanged. Furthermore, a high pain expectancy co-occurred with (1) a marginally significant fear of (re)injury, and (2) a significant lower peak torque of the knee flexors. These results are consistent with conditioning models which state that pain expectations are associated with a fear response and an urge to avoid the pain.     

Does experienced pain affects local brain volumes? Insights from a clinical acute pain model

Background/Objective:To study pain-brain morphometry associations as a function of post-surgery stages (anesthesia, pain and analgesia) in an acute pain model. Method:Impacted mandible third molar were extracted. Before surgery, an anatomical T1 scan was obtained. Regional brain volumen and subcortical nuclei shapes were obtained. Statistical analyses were done using multiple regression, being pain scores the predictors and voxel volumes, subcortical nuclei volumes and subcortical nuclei shapes, the outcomes. Results:Pain was significantly larger at pain than at anesthesia and analgesia stages, and was higher during anesthesia than during analgesia. Pain intensity was related to grey matter in several cortical (Insula, Mid Frontal and Temporal Gyruses, Precuneus, Anterior Cingulate), and subcortical nuclei (Hippocampus, Thalamus, Putamen, Amygdala), depending of the post-surgical stage. A larger number of brain areas showed significance at pain that at anesthesia and analgesia stages. Conclusions:The relationships of regional brain volumes and subcortical nuclei shapes with pain scores seemed to be unsteady, as they changed with the patient's actual pain stage.     

Does self-efficacy moderate intensity of pain?

75 subjects were randomly assigned to five self-efficacy conditions (High-High, High-Low, Low-High, Low-Low, and Control) in a 5 x 3 (condition x trial) design. Pressure was applied three times to an exposed finger. After baseline, subjects received false biofeedback (i.e., independent of ratings of pain) that their ability to regulate intensity of pain was either good (High-High and High-Low) or poor (Low-High and Low-Low), or there was no biofeedback (Control). After a second trial, subjects were told that their biofeedback indicated either good (High-High and Low-High) or poor (High-Low and Low-Low) regulatory ability, or they were not given biofeedback (Control). They then received a final trial. Before each trial, subjects recorded self-efficacy expectations for regulating intensity of pain. Mixed multivariate analyses of variance on ratings of intensity and self-efficacy expectations did not yield hypothesized interactions for condition x trial.     

Assessing the “chronic pain family”

As the place of the family within the chronic pain experience gains recognition, clinicians are faced with the challenge of incorporating a family assessment within the overall evaluation process of this health problem. Two perspectives on evaluating the family of the chronic pain patient are presented in this paper. Issues central to conducting a family assessment are identified and addressed.     

Why a family perspective for pain?

Although it is well established that families have a strong influence on individuals' beliefs and behaviors related to health and illness, relatively little attention has been devoted to the family's role in the development, maintenance, and treatment of pain or to the impact of chronic pain in one family member upon other family members. A major source of information about pain and how to respond to pain symptoms is learned within the family setting. This article reviews ways in which pain conceptualizations are developed in the family and highlights the need to more carefully study health as well as dysfunctional family reactions to chronic pain. A case example is presented that details the far reaching consequences that chronic pain can have on family life. It is concluded that more careful research, particularly in terms of the operationalization of theoretical constructs and the reliable assessment of these constructs, is needed before any definitive statements can be made about the importance and characteristics of pain-family transactions.     

Does physical pain impair abstract thinking?

The ability to think abstractly constitutes a fundamental dimension of human cognition. Although abstraction has been extensively studied, its emotional and affective antecedents have been largely overlooked. One experiment was conducted to examine whether physical pain affects abstraction. Drawing on Construal Level Theory [Trope, Y., &; Liberman, N. (2010). Construal-level theory of psychological distance. Psychological Review, 117, 440–463] and Loewenstein’s [(1996). Out of control: Visceral influences on behavior. Organizational Behavior and Human Decision Processes, 65, 272–292] visceral factors theory, we hypothesised that pain impairs abstraction because pain constricts people’s mental horizons and lead to a concrete, inward-focus toward oneself in the here and now. Physical pain was manipulated between subjects (N?=?150). The participants either kept their left hand immersed in cold (painful) water or neutral (painless) water while we measured abstract versus concrete behaviour identification, categorisation, and perceptual processing. Bayesian statistical analyses indicate substantial evidence against the hypothesis that pain impairs abstraction. In contrast to many other previously studied cognitive outcomes (e.g. attention), abstraction appears to be largely immune to acute, experimentally induced pain.     

The fear-avoidance model of exaggerated pain perception—II: Preliminary studies of coping strategies for pain

The personal history of pain and personal coping strategies for pain are two of the contributory factors in the Fear-Avoidance Model of exaggerated pain perception proposed by Lethem, Slade, Troup and Bentley (1983, this issue, pp. 401–408). In order to test this aspect of the hypothesis, a questionnaire was designed and has been completed by 165 students (93 female, 72 male) at the University of Liverpool.They were asked about the severity of externally-produced pain (e.g. fracture), of internally-produced pain (e.g. headache) and of back pain; about the strategies they adopted for coping with internallyproduced pain (e.g. did they ignore the pain and carry on—an active strategy—or did they go and rest—a passive strategy); and about the effects of back pain on each of 10 activities or postures (from ‘no effect’ to ‘had to stop completely’) in order to obtain an index of back-pain avoidance.Out of 165, 91 reported previous back pain (Back Pain group) and their average rating for the severity of externally-produced pain was significantly higher than for the No Back Pain group; but there were no differences between these two groups for their coping strategies for internally-produced pain. However, of the Back Pain group with two or more previous attacks, 35 gave a history indicating decreasingly severe attacks and 28, increasingly severe: the coping strategies of the latter group for internally-produced pain were significantly more passive. The ratings for severity of back pain correlated significantly with the indices for back-pain avoidance and with the ratings for severity of internally-produced pain.These findings are in line with the prediction that personal pain history and personal coping strategies are relevant to the Fear-Avoidance Model of exaggerated pain perception and may therefore influence the adoption of an avoidance or a confrontation response by the patient with chronic back pain.     

Why do people tend to overpredict pain? On the asymmetries between underpredictions and overpredictions of pain

After an underpredicted painful experience people tend to expect increased pain levels for a considerable time, despite disconfirmatory experiences. Underpredictions also tend to raise long-lasting fear and increased physiological responding. Overpredicted pain does not have such dramatic effects. What are the reasons for this asymmetry? Evidence for and against the hypothesis that underpredicted pain hurts more than correctly predicted pain, and that overpredictions result from a tendency to avoid the extra aversiveness of underpredictions, is reviewed. Based on recent experiments this explanation is rejected, and alternative explanations are discussed. It is reasoned that the most plausible explanation is that the organism automatically infers danger from an underprediction, because of the loss of predictability into the dangerous direction (i.e. more pain). Elevated expectancy and fear levels are the result of this. A modified stimulus-comparator model that accounts for the differential effects of both types of incorrect predictions is suggested. In contrast to previous models, such a model hypothesizes: (i) differential processing of under- and overpredictions; and (ii) different processes involved in the influence of expectations on subjective and non-subjective pain responses.     

Suffering: Valuable or just useless pain?

It is a commonly held view, buttressed by utilitarian considerations, that pain and suffering are valueless and not to be borne. Moreover, it is this thought, that they are valueless, which is often deployed in arguing for euthanasia for the terminally ill or those with mental or physical disability. This essay argues that suffering is inextricably part of the human condition and that it is our response to it that determines whether we are ennobled or degraded by it. While it is not sought for itself, suffering provides human beings with the opportunity to be ennobled, to be given unexpected experiences of love and to gain improbable sources of strength and so it can have a use which can make it valuable.     

Is pain sensitivity associated with dental avoidance?

The present investigation examined whether pain sensitivity is associated with dental avoidance. Whereas the aim of the first study was to determine whether pain sensitivity can be distinguished from dental fears and health concerns, the aim of the second study was to examine the structure of cognitive aspects of pain sensitivity, and the aim of the third study was to examine the relationships of pain sensitivity to anxiety sensitivity, fear, pain, and avoidance. In the first study (n = 222), a factor analysis performed with items from the Dental Phobia and Pain Sensitivity Inventory distinguished a pain sensitivity factor from factors relating to dental phobia and health concerns. The factor structure of the Pain Sensitivity Index was examined in the second study (n = 181), and similarly, a pain sensitivity factor was interpreted in the data. The third study (n = 65) found that although pain sensitivity correlated significantly with anxiety sensitivity, these constructs are not identical to each other. For instance, pain sensitivity but not anxiety sensitivity correlated significantly with blood-injury phobia. Pain sensitivity should be taken into account in future studies of dental phobia as pain sensitivity was found to be predictive of pain intensity, and pain intensity was found to be predictive of dental avoidance.     

How does persistent pain develop? An analysis of the relationship between psychological variables, pain and function across stages of chronicity

The fear-avoidance model is an attempt to underscore the importance of cognitive and behavioral factors, in a chain of events linking pain to disability. However, it is not clear at what time point the psychological variables within the model begin to be prominent. The aim of this study was to investigate the role of these psychological variables in the development of a chronic musculoskeletal pain problem. Three stages of chronicity, defined by duration of pain, provided a proxy for the developmental process: <1 year (N=48), 1-3 years (N=47) and >3 years (N=89). Subjects completed questionnaires on fear of movement, catastrophizing, depression, pain and function. The results indicate that the relationship between fear of movement and function is moderated by the stage of chronicity. Regression analyses showed that fear of movement did not explain any variance in the group with pain duration <1 year. Fear of movement did explain variance in the groups with pain duration of 1-3 years and >3 years. This suggests that the time point in the development of a musculoskeletal pain problem might be an essential aspect of the importance of the relationship between psychological components and function.     

Does sex moderate the relationship between anxiety and pain?

Objectives : Sex differences exist in the relationship between anxiety and pain, although findings are mixed. One reason could be because a number of anxiety measures have been used. Therefore, this study aimed to identify the core components within commonly used pain anxiety measures, and see whether these components are differentially related to sensation and pain thresholds in men and women.

Design, main outcome measures : One hundred and eighty-nine healthy adults (119 female) completed the Fear of Pain Questionnaire, Pain Catastrophising Scale, Pain Anxiety Symptoms Scale, Anxiety Sensitivity Index-3 and the Depression Anxiety Stress Scale. Thermal sensation and pain thresholds, mechanical sensation and pressure pain thresholds were also collected.

Results : A Principal Components Analysis of anxiety measures revealed three constructs: general distress, cognitive intrusion and fear of pain from injury/insult. Sex did not moderate the relationship between these anxiety constructs and sensation/pain thresholds. However, a significant main effect of sex was found to predict thermal pain thresholds.

Conclusion : Preliminary indications suggest that pain anxiety dimensions can be reduced to three core constructs, and used to examine pain sensation. However, sex did not moderate this relationship. Further research is required to establish the extent and strength of sex differences in the relationship between anxiety and pain.     

Hearing others’ pain: neural activity related to empathy

The human voice is one of the principal conveyers of social and affective communication. Recent neuroimaging studies have suggested that observing pain in others activates neural representations similar to those from the first-hand experience of pain; however, studies on pain expressions in the auditory channel are lacking. We conducted a functional magnetic resonance imaging study to examine brain responses to emotional exclamations of others’ pain. The control condition comprised positive (e.g., laughing) or negative (e.g., snoring) stimuli of the human voice that were not associated with pain and suffering. Compared to these control stimuli, pain-related exclamations elicited increased activation in the superior and middle temporal gyri, left insula, secondary somatosensory cortices, thalamus, and right cerebellum, as well as deactivation in the anterior cingulate cortex. The left anterior insular and thalamic activations correlated significantly with the Empathic Concern subscale of the Interpersonal Reactivity Index. Thus, the brain regions involved in hearing others’ pain are similar to those activated in the empathic processing of visual stimuli. Additionally, the findings emphasise the modulating role of interindividual differences in affective empathy.     

The resentful sucker: Do rewards ease the pain?

In a cross-sectional field study we found, as predicted, that performance differences between members of semi-autonomous teams were associated with feelings of unfairness. On the basis of equity theory we hypothesized that the relationship between performance differences and unfairness feelings would be moderated for suckers, i.e., team members with relatively high performances, who feel highly rewarded for their efforts, either with high financial rewards, with high task rewards, or with high social rewards. The results showed that financial rewards had no moderating effects, but high social rewards and low task rewards moderated feelings of unfairness for suckers.     

How do I cope with pain? Let me count the ways: awareness of pain coping behaviors and relationships with depression and anxiety

Patients with chronic pain are often undertreated with medications alone and need alternative ways of coping. Identifying pain coping skills patients use may be beneficial; however, no research has investigated whether patients are aware of their coping skills. The purpose of this study was to determine whether patients are aware of their pain coping skills, whether certain patient characteristics were related to using coping strategies, and whether coping strategies were related to psychiatric symptoms. Chart reviews were conducted on seventy-eight chronic pain patients who completed a semi-structured psychological interview. Patients endorsed using more coping strategies on the measure compared to the verbal self-report. Identifying with certain patient demographics was related to higher use of some coping strategies. Symptoms of anxiety and depression were also related to the use of some coping strategies. Anxiety was negatively related to ignoring the pain and using self-talk coping statements and positively related to catastrophizing. Depression was negatively related to the use of distraction, ignoring the pain, and using self-talk coping statements. Depression and pain severity were both positively related to catastrophizing and prayer. Results suggest that clinicians may need to help patients become aware of adaptive coping strategies they already use and that the use of certain coping strategies is related to lower levels of depression and anxiety.