Lower-order pain-related constructs are more predictive of cold pressor pain ratings than higher-order personality traits

The different impacts of pain-related negative emotion and trait negative emotion on brain function in patients with inflammatory bowel disease

Inflammatory bowel diseases (IBD) are a group of chronic, non-specific intestinal diseases that could comorbid with varieties of negative emotional constructs, including pain-related negative emotions and trait negative emotions; however, the link between brain functions and different dimensions of negative emotions remains largely unknown. Ninety-eight patients with IBD and forty-six healthy subjects were scanned using a 3.0-T functional magnetic resonance imaging scanner. The amplitudes of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality (DC) were used to assess resting-state brain activity. Partial least squares (PLS) correlation was employed to assess the relationship among abnormal brain activities, pain-related and trait negative emotions. Compared to controls, patients with IBD exhibited higher values of ALFF in the right anterior cingulate cortex (ACC), lower values of ALFF in the left postcentral gyrus, and higher values of DC in the bilateral ACC. Multivariate PLS correlation analysis revealed the brain scores of the ACC were correlated with pain-related negative emotions, the brain salience in the left postcentral gyrus was associated with the higher-order trait depression. These findings can enhance our comprehension of how pain-related negative emotion and trait negative emotion affect the brains of patients with IBD in distinct ways.

Assessing how individuals conceptualize numeric pain ratings: validity and reliability of the Pain Schema Inventory (PSI-6) Short Form

Background

While numeric scales to represent pain intensity have been well validated, individuals use various conceptualizations when assigning a number to pain intensity, referred to as pain rating schema. The 18-item Pain Schema Inventory (PSI-18) quantifies pain rating schema by asking for numeric values for multiple mild, moderate or severe pain conditions. This study aimed to assess the validity and reliability of a shortened form of the PSI, using only 6 items (PSI-6).

Methods

A secondary analysis was performed on two existing datasets. The first (n = 641) involved a community-based population that completed the PSI-18. The second (n = 182) included participants with chronic pain who completed the PSI-6 twice, one week apart. We assessed face validity, convergent validity, offset biases, test-retest reliability, and internal consistency of the PSI-6 compared to the PSI-18.

Results

Both the PSI-18 and PSI-6 demonstrated excellent face validity. The PSI-6 demonstrated excellent convergent validity relative to the PSI-18, with correlations from r = 0.88 to 0.92. Bland-Altman plots revealed offset biases near zero (< 0.22 on 0-10 scale) across all categories of mild, moderate, severe and average pain. Internal consistency was excellent, with Cronbach's Alpha = 0.91 and 0.80, for PSI-18 and PSI-6 respectively. Test-retest reliability of the PSI-6 was high with correlations from r = 0.70-0.76.

Conclusion

The PSI-6 is a valid and reliable tool to assess pain rating schema with reduced subject burden, to better interpret individuals' pain ratings and adjust for inter-individual variability.

The role of neuroticism and pain in dental anxiety: A twin study

OBJECTIVES

Accumulating evidence has revealed that dental anxiety is robustly associated with dental care-related pain and discomfort, but also with the personality trait of neuroticism (i.e. the relatively stable disposition to experience the world as distressing, threatening and unsafe). However, there is a near absence of research on these risk factors in samples for which genetic information is available. With the aim of arriving at a more refined understanding of dental anxiety, this twin cohort study assessed genetic and environmental influences on neuroticism, dental care-related pain and dental anxiety, and the relation between these phenotypes.

METHODS

Participants were recruited from the Norwegian Twin Registry, and data collections were carried out in 1992-98 (Time 1) and 2011 (Time 2). Well-validated questionnaires were used to assess the study variables, including Corah's Dental Anxiety Scale, the Numerical Pain Rating Scale, the NEO Personality Inventory Revised (Time 2) and Eysenck's Personality Questionnaire (Time 1). Pearson correlation analysis and generalized estimating equations (GEE) were used to investigate phenotypic associations. Analyses of genetic and environmental influences were performed using Cholesky modelling.

RESULTS

A total of 746 monozygotic (MZ) and 770 dizygotic (DZ) twins in the age group of 50-65 participated in the study. Moderate estimates of heritability for dental anxiety (0.29), treatment-related pain (0.24) and neuroticism (0.45-0.54) were found. Cholesky modelling showed furthermore that neuroticism assessed at Time 1 and Time 2 was related to dental anxiety and pain via both genetic and individual-specific environmental pathways, albeit not very strongly. The particularly high phenotypic correlation observed between dental care-related pain and anxiety (r = .68) was explained by both overlapping genetic and individual-specific environmental influences (the genetic and environmental correlations were .84 and .63 respectively).

CONCLUSIONS

The findings provide deeper insight into the aetiology of dental anxiety and confirm that while it is strongly linked to treatment-related pain experiences, this relation is to a considerable degree independent of general negative affectivity/neuroticism.

Reduced Spinal Cord Gray Matter in Patients with Fibromyalgia Using Opioids Long-term

Objective

Chronic pain involves alterations in brain gray matter volume (GMV). Moreover, opioid medications are known to reduce GMV in numerous brain regions involved in pain processing. However, no research has evaluated (1) chronic pain-related GMV alterations in the spinal cord or (2) the effect of opioids on spinal cord GMV. Accordingly, this study evaluated spinal cord GMV in health controls and patients with fibromyalgia who were using and not using opioids long-term.

Methods

We analyzed average C5 - C7 GMV of the spinal cord dorsal and ventral horns in separate female cohorts of healthy controls (HC, n = 30), fibromyalgia patients not using opioids (FMN, n = 31), and fibromyalgia patients using opioids long-term (FMO, n = 27). To assess the effect of group on average dorsal and ventral horn GMV, we conducted a one-way multivariate analysis of covariance.

Results

After controlling for age, we observed a significant effect of group on ventral horn GMV (p = 0.03, η2 = 0.09), and on dorsal horn GMV (p = 0.05, η2 = 0.08). Tukey's posthoc comparisons showed that, compared to HC participants, FMOs had significantly lower ventral (p = 0.01) and dorsal (p = 0.02) GMVs. Among FMOs only, ventral horn GMV was significantly positively associated with pain severity and interference, and both dorsal and ventral GMVs were significantly positively associated with cold pain tolerance.

Conclusion

Long-term opioid use may impact sensory processing in fibromyalgia via gray matter changes within the cervical spinal cord.

Multisensory sensitivity differentiates between multiple chronic pain conditions and pain-free individuals

ABSTRACT

Multisensory sensitivity (MSS) to nonpainful stimuli has been identified as a risk factor for the presence of coexisting chronic pain conditions. However, it remains unclear whether MSS can differentiate pain phenotypes involving different levels of central sensitivity. Both pain-free and those with chronic pain, particularly fibromyalgia (FM), migraine, or low back pain (LBP) were recruited, with pain comorbidities assessed. MSS was highest in FM, followed by migraine, then LBP, and lowest in pain-free individuals (adjusted between condition Cohen d = 0.32-1.2, P ≤ 0.0007). However, when secondly grouping patients by the total number of pain comorbidities reported, those with a single pain condition (but not FM) did not have significantly elevated MSS vs pain-free individuals (adj d= 0.17, P = 0.18). Elevated MSS scores produced increased odds of having 2 or more pain comorbidities; OR [95% CI] =2.0 [1.15, 3.42], without, and 5.6 [2.74, 11.28], with FM ( P ≤ 0.0001). Furthermore, those with low MSS levels were 55% to 87% less likely to have ≥ 2 pain comorbidities with or without FM (OR 0.45 [0.22, 0.88]-0.13 [0.05, 0.39]; P ≤ 0.0001). Our findings support that MSS can differentiate between pain phenotypes with different degrees of expected central mechanism involvement and also serve as a risk and resilience marker for total coexisting chronic pain conditions. This supports the use of MSS as a marker of heightened central nervous system processing and thus may serve as a clinically feasible assessment to better profile pain phenotypes with the goal of improving personalized treatment.

Knowing what you feel: Inferior frontal gyrus-based structural and functional neural patterns underpinning adaptive body awareness

BACKGROUND

Heightened body awareness (BA) is conducive for increasing understanding of bodily state and improves individuals' health and well-being. Although there has been cumulative research concentrating on the self-perceived tendency to focus on negatively valenced interoceptive sensations, the specific structural and functional neural patterns underlying BA and their role in the relationship between BA and individual well-being remain unclear.

METHODS

Voxel-based morphometry and whole brain functional connectivity analyses were conducted to examine the structural and functional neural patterns, respectively, in 686 healthy subjects. BA and subjective well-being were assessed using questionnaires.

RESULTS

BA was inversely related to gray matter volume of the right inferior frontal gyrus, opercular part (IFGoperc). Higher BA was correlated with enhanced IFGoperc-precuneus and IFGoperc-anterior supramarginal gyrus connectivities, and with decreased IFGoperc-lateral occipital cortex and IFGoperc-medial frontal cortex connectivities. The inferior frontal gyrus, triangular part (in the fronto-parietal task control network) acted as the hub that linked the sensory/somatomotor network, the default mode network, and the dorsal and ventral attention network. The IFGoperc-precuneus connectivity moderated the association between BA and subjective well-being.

LIMITATIONS

We were unable to rank all the networks by their relative importance, because the absolute weighted value in each module was not calculated.

CONCLUSION

Our findings demonstrated that BA was reflected by specific neural patterns mainly involved in cognitive-affective control, attentional and self-referential processing, as well as multisensory integration, which could offer some references for current therapies (e.g., mindfulness, yoga training) that are dedicated to solving health problems and improving individual well-being.

The role of negative emotions in sex differences in pain sensitivity

Pain perception varies widely among individuals due to the varying degrees of biological, psychological, and social factors. Notably, sex differences in pain sensitivity have been consistently observed in various experimental and clinical investigations. However, the neuropsychological mechanism underlying sex differences in pain sensitivity remains unclear. To address this issue, we quantified pain sensitivity (i.e., pain threshold and tolerance) using the cold pressure test and negative emotions (i.e., pain-related fear, pain-related anxiety, trait anxiety, and depression) using well-established questionnaires and collected magnetic resonance imaging (MRI) data (i.e., high-resolution T1 structural images and resting-state functional images) from 450 healthy subjects. We observed that, as compared to males, females exhibited lower pain threshold and tolerance. Notably, sex differences in pain sensitivity were mediated by pain-related fear and anxiety. Specifically, pain-related fear and anxiety were the complementary mediators of the relationship between sex and pain threshold, and they were the indirect-only mediators of the relationship between sex and pain tolerance. Besides, structural MRI data revealed that the amygdala subnuclei (i.e., the lateral and basal nuclei in the left hemisphere) volumes were the complementary mediators of the relationship between sex and pain-related fear, which further influenced pain sensitivity. Altogether, our results provided a comprehensive picture of how negative emotions (especially pain-related negative emotions) and related brain structures (especially the amygdala) contribute to sex differences in pain sensitivity. These results deepen our understanding of the neuropsychological underpinnings of sex differences in pain sensitivity, which is important to tailor a personalized method for treating pain according to sex and the level of pain-related negative emotions for patients with painful conditions.

Investigating Attachment Insecurity and Somatosensory Amplification, and the Mediating Role of Interpersonal Problems

Abstract. Background: Somatosensory amplification involves perceptual sensitivity to and cognitive-affective interpretation of bodily sensations and external stimuli, contributing to heightened experiences of somatic symptoms. However, little is known about somatosensory amplification in relation to vulnerabilities such as attachment insecurity. Aims: The present study investigated the link between attachment insecurity and somatosensory amplification, including the mediating role of dysfunctional interpersonal behaviors. Method: A sample of 245 adult community members completed the Somatosensory Amplification Scale, Generalized Anxiety Disorder Scale, and abbreviated versions of the Experiences in Close Relationships scale and Inventory of Interpersonal Problems. Correlational and regression analyses were used to examine relations among study variables, including a hypothesized parallel mediation model. Results: Somatosensory amplification was significantly associated with attachment anxiety, but not attachment avoidance. Regression analyses, controlling for general anxiety symptoms and gender, found that interpersonal sensitivity (but not aggression or ambivalence) mediated the link between attachment anxiety and somatosensory amplification. Limitations: Study limitations include the use of cross-sectional data and a non-clinical sample. Conclusion: The findings indicate that somatosensory amplification may be related to individuals’ attachment anxiety, through the mediating effect of interpersonal sensitivity problems.

More Insight on the Role of Personality Traits and Sensitivity to Experimental Pain

Purpose

The present study aimed to assess the influence of personality traits on the variability of sensitivity to pain in two distinct groups of healthy subjects with low versus high sensitivity to pain (LSP vs HSP, respectively).

Methods

Healthy subjects (n=156) were allocated to two groups according to their tolerability to cold stimulation (cold pressor test, CPT, 1°C). Group LSP (n=76) reached the cut-off time of 180±0 sec, and a size matched group of HSP (n=80) tolerated the CPT for an average of 10.5±3.4 sec only. Subjects from both groups completed the self-reported pain sensitivity questionnaire (PSQ), the Pain Catastrophizing Scale (PCS), and the Neuroticism Extraversion Openness - Five Factor Inventory (NEO-FFI).

Results

In comparison to the LSP group, HSP individuals had higher scores of PSQ (p<0.001), catastrophizing (p=0.001), and extraversion (p=0.01). By adjusting for age and gender, mediation analyses revealed that catastrophizing mediated the relationship between neuroticism and pain sensitivity, both in the allocation of subjects to a certain group of sensitivity to pain (LSP or HSP, B=0.02 95% CI: 0.006–0.040) and in the PSQ score (B=0.01 95% CI: 0.001–0.023).

Conclusion

These results, which were demonstrated by two different prisms (CPT and PSQ), point to the potential of the five-factor inventory and pain catastrophizing scale as tools for identifying specific personality traits associated with a high sensitivity to pain.

Effects of anxiety-related psychological states on music-induced analgesia in cold pressor pain responses

CONTEXT

The analgesic effect of music has long been reported.

OBJECTIVE

To assess how anxiety-related psychological states affect the analgesic effect of music using the cold pressor task (CPT).

DESIGN

A 3-period × 3-sequence crossover design was adopted; three conditions were used: "no sound," "music-listening," and "news-listening."

SETTING

PARTICIPANTS: Forty-nine participants were included.

INTERVENTIONS

After completing five anxiety-related psychological instruments (Anxiety Sensitivity Index [ASI]-16, ASI-Revised, State-Trait Anxiety Inventory [STAI]-S, STAI-T, and Pain Anxiety Symptoms Scale-20), the participants were allocated to the low- or high-anxiety group. The high- and low-anxiety groups were defined based on cutoff points according to the distributions and characteristics of the five instruments.

MAIN OUTCOME MEASURES

Pain responses, such as pain tolerance time, pain intensity, and pain unpleasantness, were measured on the CPT. Pain responses in the music-listening condition were also compared to those in the other two conditions via pairwise comparisons within each anxiety group.

RESULTS

The Cronbach alpha of the five instruments ranged from 0.866 to 0.95, indicating that they were reliable. Pain responses in the music-listening condition in the low-anxiety groups based on any of the five scales were significantly different from those in the other conditions, but this effect was not found in the high-anxiety groups. This study demonstrates that anxiety-related psychological states can predict the analgesic effect of music on pain responses measured by the CPT and suggests that music may be beneficial as a pain management tool in low-anxiety groups.

Multisensory Sensitivity is Related to Deep-Tissue but Not Cutaneous Pain Sensitivity in Healthy Individuals

PURPOSE

Some individuals with chronic pain find daily life sensations (eg, noise, light, or touch) aversive. This amplification of multisensory sensations has been associated with centrally mediated plasticity; for example, greater multisensory sensitivity (MSS) occurs in patients with fibromyalgia than rheumatoid arthritis. However, whether MSS preferentially relates to pain measures which reflect central influences (eg, dynamic quantitative sensory testing (QST) or referred pain), or whether the MSS-pain relationship requires priming from chronic pain, is unknown. Thus, this cross-sectional study investigated the relationships between MSS assessed in a pain-free state and evoked pain sensitivity.

METHODS

Experimental intramuscular infusion pain and multiple static and dynamic QST were assessed in 465 healthy, pain-free adults: pain thresholds using pressure (PPTs) and heat (HPTs), temporal summation of pain (TSP) using pressure, heat or punctate stimuli, and conditioned pain modulation (CPM) using pressure or heat test stimuli. MSS was assessed using 7 items from Barsky's Somatosensory Amplification Scale. Differences in pain and QST between sex-specific MSS quartiles were assessed, adjusting for multiple comparisons. All participants completed at least one intramuscular infusion condition, but not all were asked to complete each QST (n=166-465).

RESULTS

Both static and dynamic QST differed between highest and lowest MSS quartiles using pressure stimuli: lower PPTs (adjusted-p<0.01); increased pressure TSP (adjusted-p=0.02); lower pressure CPM (adjusted-p=0.01). However, none of the heat or punctate QST measures (HPTs, TSP, or CPM) differed between MSS quartiles (adjusted-p>0.05). Odds of experiencing TSP or referred pain was not greater, whereas CPM was 8-fold less likely, in those with highest MSS.

CONCLUSION

Normal variation in non-noxious MSS is related to both static and dynamic pain sensitivity, without sensitization associated with chronic pain, but is dependent on the QST stimulus. Thus, common influences on MSS and pain sensitivity may involve central mechanisms but are likely more complex than previously recognized.

Testing a positive-affect induction to reduce verbally induced nocebo hyperalgesia in an experimental pain paradigm

There is an ethical obligation to notify individuals about potential pain associated with diagnoses, treatments, and procedures; however, supplying this information risks inducing nocebo hyperalgesia. Currently, there are few empirically derived strategies for reducing nocebo hyperalgesia. Because nocebo effects are linked to negative affectivity, we tested the hypothesis that a positive-affect induction can disrupt nocebo hyperalgesia from verbal suggestion. Healthy volunteers (N = 147) were randomly assigned to conditions in a 2 (affect induction: positive vs neutral) by 2 (verbal suggestion: no suggestion vs suggestion of pain increase) between-subjects design. Participants were induced to experience positive or neutral affect by watching movie clips for 15 minutes. Next, participants had an inert cream applied to their nondominant hand, and suggestion was manipulated by telling only half the participants the cream could increase the pain of the upcoming cold pressor test. Subsequently, all participants underwent the cold pressor test (8 ± 0.04°C), wherein they submerged the nondominant hand and rated pain intensity on numerical rating scales every 20 seconds up to 2 minutes. In the neutral-affect conditions, there was evidence for the nocebo hyperalgesia effect: participants given the suggestion of pain displayed greater pain than participants not receiving this suggestion, P's < 0.05. Demonstrating a blockage effect, nocebo hyperalgesia did not occur in the positive-affect conditions, P's > 0.5. This is the first study to show that positive affect may disrupt nocebo hyperalgesia thereby pointing to a novel strategy for decreasing nocebo effects without compromising the communication of medical information to patients in clinical settings.

Pain Processing in Elite and High-Level Athletes Compared to Non-athletes

Background

Previous studies shows that elite and high-level athletes possess consistently higher pain tolerance to ischemic and cold pain stimulation compared to recreationally active. However, the data previously obtained within this field is sparse and with low consistency.

Purpose

The aim of the present study was to examine the difference in pain perception between elite and high-level endurance athletes (cross country skiers and runners), elite soccer players and non-athletes, as well to explore the impact of psychological factors on pain processing.

Methods

Seventy one healthy volunteers (33 females and 38 males) participated in the study. Soccer players (n = 17), cross country skiers (n = 12), and long-distance runners (n = 3) formed the athlete group, with 39 non-athletes as controls. Big-five personality traits, fear of pain and Grit (perseverance and passion for long-term goals) were measured prior to induction of experimental pain. Pain threshold and intensity was induced by a PC-controlled heat thermode and measured by a computerized visual analog scale. Pain tolerance was measured by the cold pressor test (CPT).

Results

Elite and high-level athletes had increased pain tolerance, higher heat pain thresholds, and reported lower pain intensity to thermal stimulation. Endurance athletes (cross country skiers and long-distance runners) had better tolerance for cold pain compared to both soccer-players and non-athletes. Furthermore, endurance athletes reported lower pain intensity compared to non-athletes, whereas both endurance athletes and soccer players had higher heat pain thresholds compared to non-athletes. Fear of Pain was the only psychological trait that had an impact on all pain measures.

Conclusion

The present findings suggest that sports with long durations of physically intense activity, leveling aerobic capacity, are associated with increased ability to tolerate pain and that the amount of training hours has an impact on this tolerance. However, the small sample size implies that the results from this study should be interpreted with caution.

Is Prick of Conscience Associated With the Sensation of Physical Prick?

"Prick of conscience" is a phrase to express feelings of guilt in both English and Korean. Particularly in South Korea, guilt is metaphorically associated with a sense of touch by pricking. Koreans commonly express feelings of guilt by using the metaphor, "It pricks my conscience." Across three studies, we examined whether prick of conscience (i.e., feelings of guilt) is grounded in bodily experiences of physical prick (e.g., a needle prick), using a sample of Koreans. Participants who recalled past unethical acts were less likely to choose a needle prick rather than medication as a treatment for indigestion, whereas those who recalled ethical acts presented no significant difference in their willingness to receive either treatment (Study 1). Participants who decided to lie sensed the finger prick deeper and felt more pain as compared to those in the truth group or the control group (Study 2). Lastly, participants who had the finger prick rendered harsher moral judgments than participants in the control condition (Study 3). In line with an embodied cognition framework, these findings suggest that prick of conscience is not just a linguistic metaphor but can be embodied as physical sensations in forms of pricking.

Psychologic Factors Do Not Affect Placebo Responses After Upper Extremity Injections: A Randomized Trial

BACKGROUND

Studies on how psychologic factors influence the placebo effect have shown conflicting results in an experimental setting. Pessimists are more likely to experience a nocebo effect (feel worse after an inert intervention), whereas other studies suggest that patients with more symptoms of depression or anxiety or greater neuroticism have a greater response to a placebo. This is important because treatment benefits are potentiated by placebo effects, and optimal utilization of this phenomenon may improve clinical outcomes.

QUESTIONS/PURPOSES

(1) What psychologic factors are associated with a decrease in magnitude of limitations (Disabilities of the Arm, Shoulder and Hand [DASH] score) and pain intensity (visual analog scale [VAS] for pain) after placebo injections for the treatment of painful nontraumatic upper extremity conditions? (2) What psychologic factors are associated with achieving a minimum clinically important difference (MCID) in disability and pain intensity?

METHODS

We performed a secondary analysis of data acquired in two prospective, double-blind, randomized controlled trials of patients with lateral elbow pain, trapeziometacarpal arthrosis, and de Quervain tendinopathy who received a single injection of dexamethasone and lidocaine or lidocaine alone (placebo). One hundred six patients were included between June 2003 and February 2008. Sixty-three patients (59%) received dexamethasone and lidocaine, and we analyzed the subset of 43 patients (41%) who received lidocaine alone. The primary outcomes of interest were the DASH questionnaire and the VAS for pain measured three times: when they received the injection, between 1 and 3 months after the injection, and between 5 and 8 months after the injection. Seven patients missed the first followup visit and 14 patients missed the second visit. Based on previous research, we chose a MCID threshold of 10 for the DASH and a threshold of 1.0 for the VAS score. In bivariate analysis, we accounted for sex, race, marital status, degree, education, work status, pretreatment pain, diagnosis, symptoms of depression (Center of Epidemiologic Studies-Depression Scale), coping strategies in response to nociception (Pain Catastrophizing Scale), and personality traits (measured with the Multidimensional Health Locus of Control scale and the Eysenck Personality Questionnaire-Revised score). Variables with p values < 0.10 in bivariate analysis were included in the multivariable regression models. An a priori power analysis showed that a sample of 43 participants provides 80% statistical power, with α set at 0.05, for a regression with five predictors if the depression score would account for 15% or more of the variability in pain score. We used multiple imputations (imputations = 50) for a total of 66 (8.5%) missing or incomplete questionnaires.

RESULTS

In the final multivariable models, no psychologic factors were associated with a change in DASH score between injection and followup, and no factors were associated with greater decrease in pain intensity. After injection, no psychologic factors were independently associated with achieving a MCID in the DASH and VAS.

CONCLUSIONS

Our study confirms that patient factors are less important mediators of the placebo effect than clinician factors. In other words, clinician warmth and competence can help diminish symptoms and limitations of people in various states of mind, even when using inert or ineffective treatments.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Neuroticism and pain catastrophizing aggravate response to pain in healthy adults: an experimental study

Background

The aim of this study was to investigate the association between neuroticism, pain catastrophizing, and experimentally induced pain threshold and pain tolerance in a healthy adult sample from two regions of the country of Croatia: the island of Korcula and city of Split.

Methods

A total of 1,322 participants were enrolled from the Island of Korcula (n = 824) and the city of Split (n = 498). Participants completed a self-reported personality measure Eysenck Personality Questionnaire (EPQ) and pain catastrophizing questionnaire Pain Catastrophizing Scale (PCS), followed by a mechanical pain pressure threshold and tolerance test. We have explored the mediating role of catastrophizing in the relationship between neuroticism and pain intensity.

Results

The results showed that pain catastrophizing partially mediated the relationship between neuroticism and pain intensity, suggesting the importance of pain catastrophizing in increasing vulnerability to pain. The results also indicated gender-related differences, marked by the higher pain threshold and tolerance in men.

Conclusions

This study adds to the understanding of the complex interplay between personality and pain, by providing a better understanding of such mechanisms in healthy adults.

Somatosensory amplification - An old construct from a new perspective

The paper reviews and summarizes the history and the development of somatosensory amplification, a construct that plays a substantial role in symptom reports. Although the association with negative affect has been supported by empirical findings, another key elements of the original concept (i.e. body hypervigilance and the tendency of focusing on mild body sensations) have never been appropriately addressed. Recent findings indicate that somatosensory amplification is connected with phenomena that do not necessarily include symptoms (e.g. modern health worries, or expectations of symptoms and medication side effects), and also with the perception of external threats. In conclusion, somatosensory amplification appears to refer to the intensification of perceived external and internal threats to the integrity of the body ("somatic threat amplification") rather than amplification of perceived or actual bodily events only. Practical implications of this new approach are also discussed.

Prediction of persistent post-operative pain: Pain-specific psychological variables compared with acute post-operative pain and general psychological variables

BACKGROUND

Psychological variables and acute post-operative pain are of proven relevance for the prediction of persistent post-operative pain. We aimed at investigating whether pain-specific psychological variables like pain catastrophizing add to the predictive power of acute pain and more general psychological variables like depression.

METHODS

In all, 104 young male patients undergoing thoracic surgery for pectus excavatum correction were studied on the pre-operative day (T0) and 1 week (T1) and 3 months (T2) after surgery. They provided self-report ratings (pain-related: Pain Catastrophizing Scale, Pain Anxiety Symptoms Scale = PASS, Pain Vigilance and Awareness Questionnaire = PVAQ; general psychological: Screening for Somatoform Symptoms, State-Anxiety Inventory-X1, Center for Epidemiologic Studies Depression Scale = CES-D). Additional predictors (T1) as well as criterion variables (T2) were pain intensity (Numerical Rating Scale) and pain disability (Pain Disability Index).

RESULTS

Three months after surgery, 25% of the patients still reported clinically relevant pain (pain intensity ≥3) and over 50% still reported pain-related disability. Acute post-operative pain as well as general psychological variables did not allow for a significant prediction of persistent post-operative pain; in contrast, pain-related psychological variables did. The best single predictors were PASS for pain intensity and PVAQ for pain disability.

CONCLUSIONS

Pain-related psychological variables derived from the fear-avoidance model contributed significantly to the prediction of persistent post-operative pain. The best possible compilation of these measures requires further research. More general psychological variables may become relevant predictors later in the medical history.

SIGNIFICANCE

Our results suggest that pain-specific psychological variables such as pain anxiety and pain hypervigilance add significantly to the prediction of persistent post-operative pain and might even outperform established predictors such as acute pain and general psychological variables. Clinicians might benefit from the development of time-economic screening tools based on these variables.

A longitudinal exploration of pain tolerance and participation in contact sports

BACKGROUND/AIMS

Athletes who choose to engage in contact sports do so with the knowledge that participation will bring pain in the form of contact with others, injury, and from exertion. Whilst athletes who play contact sports have been shown to have higher pain tolerance than those who do not, it is unclear whether this is a result of habituation over time, or as a result of individual differences at the outset. The aim was to compare pain responses over an athletic season in athletes who participated in contact sport and those who disengaged from it.

METHODS

One hundred and two new contact athletes completed measures of cold and ischaemic pain tolerance, perceived pain intensity, pain bothersomeness, pain coping styles and attendance at the start, middle (4 months) and end (8 months) of their season. The athletes were drawn from martial arts, rugby and American football. Cluster analysis placed 47 athletes into a participating category and 55 into a non-participating cluster.

RESULTS

Participating athletes had higher ischaemic pain tolerance at the start (r=0.27, p=0.05), middle (r=0.41, p<0.0001) and end of the season (r=0.57, p<0.0001) compared to non-participating athletes. In addition participating athletes were more tolerant to cold pain at the end of the season (r=0.39, p<0.0001), compared to non-participating athletes. Participating athletes also exhibited higher direct coping, catastrophized less about injury pain and also found contact pain to be less bothersome physically and psychologically compared to non-participating athletes. Participating athletes were more tolerant of ischaemic pain at the end of the season compared to the start (r=0.28, p=0.04). Conversely non-participating athletes became significantly less tolerant to both pain stimuli by the end of the season (cold pressor; r=0.54, p<0.0001; ischaemia; r=0.43, p=0.006). Pain intensity as measured by a visual analogue scale did not change over the season for both groups.

CONCLUSIONS

Those who cease participation in contact sports become less pain tolerant of experimental pain, possibly a result of catastrophizing. The results suggest that athletes who commit to contact sports find pain less bothersome over time, possibly as a result of experience and learning to cope with pain. Athletes who continue to participate in contact sports have a higher pain tolerance, report less bothersomeness and have higher direct coping than those who drop out. In addition, tolerance to ischaemic pain increased over the season for participating athletes.

IMPLICATIONS

Having a low pain tolerance should not prevent athletes from taking part in contact sports, as pain becomes less bothersome in athletes who adhere to such activities. Participating in contact sports may result in maintained cold pain tolerance, increased ischaemic pain tolerance, reduced catastrophizing and better coping skills. Coaches can therefore work with athletes to develop pain coping strategies to aid adherence to contact sports.

Toward a genetic understanding of dental fear: evidence of heritability

OBJECTIVES

Dental fear is a prevalent problem that impacts dental treatment-seeking behavior and thus oral, systemic, and psychological health. Among other important predictors, fear of pain has been shown to be a critical component of dental fear. While learning history (id est, past experience) is known to shape development and maintenance of dental fear and fear of pain, minimal work has addressed genetic etiological variables for these healthcare-related anxieties. With the aim of coming to a more complete conceptualization of dental fear, this study assessed the heritability of dental fear and fear of pain and elucidated the role of genetics in the relation between the constructs.

METHODS

Participants (n = 1370; 827 female), aged 11-74 years (M = 29.2, SD = 12.2), in a family-based cohort study completed measures of dental fear and fear of pain. Heritability and genetic correlation were estimated using likelihood-based methods under the variance components framework.

RESULTS

Dental fear was 30% heritable (P < 0.001) and fear of pain was 34% heritable (P < 0.001). Notably, there was substantial genetic correlation between dental fear and fear of pain, ρ_G = 0.67, suggesting they are genetically related, but likely are distinct phenotypes.

CONCLUSIONS

It is clear that, in addition to environmental factors, genetic influences are important in the etiology of dental fear and anxiety and should be considered in future studies of fear and anxiety associated with dental treatment and, potentially, interventions aimed at reducing distress that is a barrier to dental treatment utilization.

Somatic Awareness and Tender Points in a Community Sample

Somatic awareness (SA) refers to heightened sensitivity to a variety of physical sensations and symptoms. Few attempts have been made to dissociate the relationship of SA and affective symptoms with pain outcomes. We used a validated measure of mood and anxiety symptoms that includes questions related to SA to predict the number of tender points found on physical examination in a large cross-sectional community sample (the Midlife in the United States [MIDUS] Biomarker study). General distress, positive affect, and SA, which were all significantly associated with tender point number in bivariate analyses, were used as predictors of the number of tender points in a multivariate negative binomial regression model. In this model a greater number of tender points was associated with higher levels of SA (P = .02) but not general distress (P = .13) or positive affect (P = .50). Follow-up mediation analyses indicated that the relationship between general distress and tender points was partially mediated by levels of SA. Our primary finding was that SA is strongly related to the number of tender points in a community sample. Mechanisms linking SA to the spatial distribution of pain sensitivity should be investigated further.

PERSPECTIVE

This article presents an analysis of 3 overlapping psychological constructs and their relationship to widespread pain sensitivity on palpation. The findings suggest that SA is most strongly related to the spatial distribution of pain sensitivity and that further assessing it may improve our understanding of the relationship between psychological factors and pain.

Effect of somatosensory amplification and trait anxiety on experimentally induced orthodontic pain

The perception of pain varies considerably across individuals and is affected by psychological traits. This study aimed to investigate the combined effects of somatosensory amplification and trait anxiety on orthodontic pain. Five-hundred and five adults completed the State Trait Anxiety Inventory (STAI) and the Somatosensory Amplification Scale (SSAS). Individuals with combined STAI and SSAS scores below the 20th percentile (LASA group: five men and 12 women; mean age ± SD = 22.4 ± 1.3 yr) or above the 80th percentile (HASA group: 13 men and seven women; mean age ± SD = 23.7 ± 1.0 yr) were selected and filled in the Oral Behaviors Checklist (OBC). Orthodontic separators were placed for 5 d in order to induce experimental pain. Visual analog scales (VAS) were administered to collect ratings for occlusal discomfort, pain, and perceived stress. Pressure pain thresholds (PPT) were measured. A mixed regression model was used to evaluate pain and discomfort ratings over the 5-d duration of the study. At baseline, the LASA group had statistically significantly higher PPT values for the masseter muscle than did the HASA group. During the experimental procedure, the HASA group had statistically significantly higher discomfort and pain. A significant difference in pain ratings during the 5 d of the study was found for subjects in the HASA group. Higher OBC values were statistically significantly positively associated with pain. Somatosensory amplification and trait anxiety substantially affect experimentally induced orthodontic pain.

Preserved emotional awareness of pain in a patient with extensive bilateral damage to the insula, anterior cingulate, and amygdala

Functional neuroimaging investigations of pain have discovered a reliable pattern of activation within limbic regions of a putative "pain matrix" that has been theorized to reflect the affective dimension of pain. To test this theory, we evaluated the experience of pain in a rare neurological patient with extensive bilateral lesions encompassing core limbic structures of the pain matrix, including the insula, anterior cingulate, and amygdala. Despite widespread damage to these regions, the patient's expression and experience of pain was intact, and at times excessive in nature. This finding was consistent across multiple pain measures including self-report, facial expression, vocalization, withdrawal reaction, and autonomic response. These results challenge the notion of a "pain matrix" and provide direct evidence that the insula, anterior cingulate, and amygdala are not necessary for feeling the suffering inherent to pain. The patient's heightened degree of pain affect further suggests that these regions may be more important for the regulation of pain rather than providing the decisive substrate for pain's conscious experience.

Modulation of the startle reflex by heat pain: does threat play a role?

BACKGROUND

Previous studies have indicated that the startle reflex is potentiated by phasic, but not by tonic, heat pain, although the latter is seen as more strongly associated with emotional responses and more similar to clinical pain. The threat value of pain might be a decisive variable, which is not influenced alone by stimulus duration.

OBJECTIVE

This study aimed at comparing startle responses to tonic heat pain stimulation with varying degrees of threat. We hypothesized that the expectation of unpredictable temperature increases would evoke higher threat and thereby potentiate startle compared with the expectation of constant stimulation.

METHODS

Healthy, pain-free subjects (n = 40) underwent painful stimulation in two conditions (low/high threat) in balanced order. The only difference between the two conditions was that in the high-threat condition 50% of the trials were announced to include a short further noxious temperature increase at the end. Startle tones were presented prior to this temperature increase still in the phase of anticipation.

RESULTS

We observed startle potentiation in the high-threat compared with the low-threat condition, but only in those participants who took part first in the high-threat condition. Habituation could not account for these findings, as we detected no significant decline of startle responses in the course of both conditions.

CONCLUSIONS

Our results suggest that subjective threat might indeed be decisive for the action of pain on startle; the threat level appears not only influenced by actual expectations but also by previous experiences with pain as threatening or not.

Trait Emotional Intelligence, Anxiety Sensitivity, and Experiential Avoidance in Stress Reactivity and Their Improvement Through Psychological Methods

Stress pervades daily society, often with deleterious consequences for those prone to react intensely to it. Intervention techniques to attenuate stress reactivity are thus paramount. With that goal in mind, researchers have sought to identify and alter malleable psychological dispositional variables that influence stress reactivity. Trait emotional intelligence (TEI), anxiety sensitivity (AS), and experiential avoidance (EA) are increasingly receiving attention in these research efforts. The self-reported emotional component of stress reactivity has been emphasized in investigations and is our focus. Specifically, this paper overviews the role of TEI, AS, and EA in self-reported stress responses. We also discuss empirically supported psychological methods to adjust suboptimal levels of these variables in normal populations. Both psycho-educational (information, skills) and mindfulness-based interventions (specific mindfulness therapies or components) are covered. Findings include that (1) TEI, AS, and EA are each correlated with the emotional component of stress reactivity to both naturalistic and lab-based stressors; (2) preliminary support currently exists for psycho-educational intervention of TEI and AS but is lacking for EA; (3) adequate evidence supports mindfulness-based interventions to target EA, with very limited but encouraging findings suggesting mindfulness methods improve TEI and AS; and (4) although more research is needed, stress management approaches based on mindfulness may well target all three of these psychological variables and thus appear particularly promising. Encouragingly, some methods to modify dispositional variables (e.g., a mindfulness-based format of guided self-help) are easily disseminated and potentially applicable to the general public.

Anxiety and anxiety sensitivity as predictors of fear of childbirth: different patterns for nulliparous and parous women

OBJECTIVE

The demographic characteristics, maternal parity and personal traits of pregnant women have been frequently studied predictors of fear of childbirth (FOC). The aim of this study was to examine the role of demographic variables, expected pain level, trait anxiety and anxiety sensitivity in FOC among nulliparous and multiparous women in the last trimester of pregnancy.

METHOD

Two-hundred pregnant women completed a booklet with questionnaires including the Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ), Anxiety Sensitivity Index (ASI), The State - Trait Anxiety Inventory (STAI) and questions on expected labor pain and demographics.

RESULTS

Results showed that FOC was higher amongst nulliparous women, but FOC level was not associated with other demographic variables. Different predictors were established in nulliparous and multiparous women. While higher intensity of expected labor pain and anxiety sensitivity (dimension physical concern) were significant predictors in both groups, trait anxiety was significant for the first-time mothers only.

CONCLUSION

Amongst all women, anxiety sensitivity (physical concerns dimension) was identified as an important vulnerability factor for FOC. As such, the level of anxiety sensitivity, and any resulting fear or expectations of pain, should be assessed in expectant mothers by clinicians in prenatal settings. Furthermore, anxiety sensitivity should be an important target for psychological interventions aimed at managing FOC.

Pain rating schema: three distinct subgroups of individuals emerge when rating mild, moderate, and severe pain

Background

While the validity of pain assessment has been well documented, the underlying schema (ie, organized, preconceived ideas) of how individuals interpret numerical pain ratings is not well understood. This study’s objectives were to examine numerical pain intensity ratings, from (0 to 10 cm on the visual analog scale [VAS]) across multiple severities of commonly experienced acute pain conditions to determine whether the ratings differed between these pain conditions and/or between individuals.

Methods

A community sample (N=365, 66% female) rated their anticipated pain intensity (VAS) for threshold, mild, moderate, severe, and tolerance level, using several common pain conditions: headache, toothache, joint injury, delayed-onset muscle soreness, burns, and “general pain.”

Results

Cluster analysis revealed three subgroups of individuals, suggesting three types of underlying pain rating schema: 1) Low Rating subgroup (low VAS pain intensity ratings across all the pain severity categories); 2) Low/High Rating subgroup (low VAS pain intensity rating for mild, but high VAS pain intensity rating for severe pain); and 3) High Rating subgroup (high VAS pain intensity ratings across all the pain severity categories). Overall, differences between pain conditions were small: muscle soreness pain intensity was consistently rated lower than the other pain types across severities. The highest pain ratings varied between joint injury and general pain, depending on severity level. No effects of sex or current experience of pain were noted.

Conclusion

The results indicate that: 1) three distinct pain schemas were present in this community-based sample, indicating significant variation in how pain scales are utilized and/or interpreted between clusters of individuals; 2) pain ratings vary by condition, but these differences are minor; and 3) pain rating schemas are not significantly different between males and females or between individuals with and without current pain.

Association of Type D personality with the autonomic and hemodynamic response to the cold pressor test

Mechanisms relating Type D personality to poor health are largely unknown, with autonomic nervous system function being a candidate. This study examined the physiologic response to cold stress. Undergraduates (N = 101, 84% female) underwent a cold pressor test. An electrocardiogram, impedance cardiogram, and blood pressure were recorded. Type D personality was assessed by self-report questionnaire. Type D was associated with increased systolic and diastolic blood pressure reactivity. Exploratory analyses showed Type D men to respond with increased respiratory sinus arrhythmia (i.e., higher parasympathetic activity), and decreased pre-ejection period (i.e., larger sympathetic activity), while Type D women showed a reciprocal response pattern. In conclusion, Type D personality was associated with an exaggerated hemodynamic response to cold stress, which may contribute to an increased risk of hypertension in Type D individuals.

The Factors Associated with Anxiety and Depression in Slovenian Armed Forces Members on a Peacekeeping Mission in the Western Balkans / Dejavniki, Povezani Z Depresijo In Tesnobnostjo Pri Slovenskih Vojakih Na Mirovni Misiji Na Zahodnem Balkanu

Objective: To identify the factors associated with the onset of depression and anxiety in professional soldiers on a peacekeeping mission in Kosovo in 2009.

Methods: A cross-sectional study of 244 members of the Slovenian Armed Forces on a peace-keeping mission, using the Depression Self Rating Scale, the Self-Rating Anxiety Scale and a background questionnaire, was performed.

Results: A 6.9% prevalence of depression and a 7.9% prevalence of anxiety were identified. The presence of a chronic pain condition and the recent termination of an intimate relationship were independently associated with the onset of either anxiety or depression or with a co-morbidity of anxiety and depression.

Conclusions: In spite of medical and psychological examinations prior to peacekeeping operations, the onset of anxiety and depression calls for special attention and empowerment by teaching peacekeepers how to use their social support and personal mastery resources.

Disposition and adjustment to chronic pain

Several empirical studies have shown that personal characteristics act as differential variables, which determine how pain is experienced and how the chronic pain patient adjusts to pain. The main aim of the present research is to review the relationships between some dispositional characteristics and pain adjustment. Taking into account the empirical literature, 6 personality traits that are relevant to the pain experience have been selected: neuroticism, anxiety sensitivity, and experiential avoidance as risk factors that increase the probability of patients experiencing a disability; and extraversion, optimism, and resilience as personal resources that increase their capacity to manage pain effectively. The results suggest that it would be useful to include an assessment of normal personality structure during the multi-dimensional evaluation of a person with chronic pain. Understanding these individual personality characteristics will aid in designing pain intervention programs and help predict possible treatment outcomes.

Unpleasant subjective emotional experiencing of pain

The field of pain medicine that once began as a supportive and compassionate care, adding value to the management of acute and chronic ailments, has now transformed into a vital and essential specialty with structured training programs and service units with professionals dedicating their careers to it. The expansion of understanding of the direct relationship of pain relief to the quality of life, uncovering of neuronal pathways, and technological advances in imaging as well as in interventional techniques have all contributed to this phenomenal growth. However, there is a growing concern whether the training programs and the specialized practitioners are gradually limiting their skilled inputs primarily within the sensory realm of the pain experience with sophisticated interventional techniques and relegating its subjective and emotional dimensions to perfunctory realms within the schema of service provision. While the specialty is still young, if we can understand the inherent aspect of these dimensions within the pain experience and acknowledge the gaps in service provision, it may be possible to champion development of truly comprehensive pain relief programs that responds effectively and ethically to a patient's felt needs. This article attempts to position the subjectivity of pain experience in context and surface the need to design complete systems of pain relief services inclusive of this dimension. It presents authors’ review of literature on perspectives of ‘unpleasant subjective emotional experiencing of the pain” to elucidate possible clinical implications based on the evidences presented on neuro-biology and neuro-psychology of the pain experience; the aim being to inspire systems of care where this dimension is sufficiently evaluated and managed.

Five-factor personality traits and pain sensitivity: a twin study

Factors underlying individual differences in pain responding are incompletely understood, but are likely to include genetic influences on basal pain sensitivity in addition to demographic characteristics such as age, sex, and ethnicity, and psychological factors including personality. This study sought to explore the relationship between personality traits and experimental pain sensitivity, and to determine to what extent the covariances between these phenotypes are mediated by common genetic and environmental factors. A sample composed of 188 twins, aged 23 to 35years, was included in the study. Heat pain intensity (HPI) and cold-pressor pain intensity (CPI) ratings were obtained using standardized pain testing procedures, and personality traits were assessed with the NEO Personality Inventory, Revised. Associations between personality and the pain sensitivity indices were examined using zero-order correlations and generalized estimating equations. Bivariate Cholesky models were used in the biometric analyses. The most robust finding was a significant phenotypic association between CPI and the personality facets Impulsiveness (a facet of Neuroticism) and Excitement-Seeking (a facet of Extraversion), and estimates of the genetic correlation were .37 (P<.05) and .43 (P<.05), respectively. In contrast, associations between HPI and personality seemed weak and unstable, but a significant effect of Angry Hostility (a facet of Neuroticism) emerged in generalized estimating equations analysis. Although the genetic correlation between these phenotypes was essentially zero, a weak but significant individual-specific environmental correlation emerged (re=.21, P<.05). Taken together, these findings suggest that CPI is more consistently related to personality dispositions than HPI, both phenotypically and genetically.

Psychological factors predict local and referred experimental muscle pain: a cluster analysis in healthy adults

BACKGROUND

Recent studies suggest an underlying three- or four-factor structure explains the conceptual overlap and distinctiveness of several negative emotionality and pain-related constructs. However, the validity of these latent factors for predicting pain has not been examined.

METHODS

A cohort of 189 (99 female, 90 male) healthy volunteers completed eight self-report negative emotionality and pain-related measures (Eysenck Personality Questionnaire - Revised, Positive and Negative Affect Schedule, State-Trait Anxiety Inventory, Pain Catastrophizing Scale, Fear of Pain Questionnaire; Somatosensory Amplification Scale, Anxiety Sensitivity Index and Whiteley Index). Using principal axis factoring, three primary latent factors were extracted: general distress, catastrophic thinking and pain-related fear. Using these factors, individuals clustered into three subgroups of high, moderate and low negative emotionality responses. Experimental pain was induced via intramuscular acidic infusion into the anterior tibialis muscle, producing local (infusion site) and/or referred (anterior ankle) pain and hyperalgesia.

RESULTS

Pain outcomes differed between clusters (multivariate analysis of variance and multinomial regression), with individuals in the highest negative emotionality cluster reporting the greatest local pain (p = 0.05), mechanical hyperalgesia (pressure pain thresholds; p = 0.009) and greater odds (2.21 odds ratio) of experiencing referred pain when compared to the lowest negative emotionality cluster.

CONCLUSION

Our results provide support for three latent psychological factors explaining the majority of the variance between several pain-related psychological measures, and that individuals in the high negative emotionality subgroup are at increased risk for (1) acute local muscle pain; (2) local hyperalgesia; and (3) referred pain using a standardized nociceptive input.

Personality traits and sick leave in workers diagnosed with nonorganic neck pain

Previous research has suggested that personality can influence the perception and reporting of physical symptoms, such as pain. To assess the relationship between the course of nonorganic neck pain and the individual's personality, we studied the association between two indicators of neck pain prognosis, such as the duration of sick leave associated with neck pain and sick leave recurrence, and 15 personality traits in a sample of 64 workers suffering from disabling neck pain without any signs of physical abnormalities in the neck area. The TEA Personality Test (TPT), a self-report instrument designed to evaluate personality traits related to organizational behaviors, was used. Compared to the normative data, the study sample obtained high scores in the Depression, Anxiety and Emotional Instability scales, thus suggesting a personality profile primarily characterized by high neuroticism-related scores. Controlling for age, gender, and any rehabilitation undergone, we found a positive relationship between Depression and the duration of sick leave (in weeks). Moreover, lower scores on the TPT personality trait Dynamism and activeness were associated with higher likelihood of sick leave recurrence. These findings highlight the need for further research into the role played by personality at the onset and in the maintenance of nonorganic neck pain. Furthermore, they suggest that a complementary psychological approach may be useful to nonorganic neck pain management.

Relationship of neuroticism and laboratory pain in healthy children: does anxiety sensitivity play a role?

Both neuroticism, a higher-order, stable personality trait, and anxiety sensitivity (AS), a lower-order pain-related construct, have been associated with pain, although no research exists examining the relationship of both these constructs to acute pain in children. In the current study, 99 healthy children (53 girls) completed self-report measures of neuroticism and AS before undergoing pain tasks involving cold and pressure pain. We hypothesized that both neuroticism and AS would be correlated with acute pain responses, but that AS would at least partially mediate the relationship between neuroticism and pain responses. Results indicated significant correlations between neuroticism, AS, and anticipatory anxiety, pain intensity and pain bother. Mediational models revealed that AS partially mediated relationships between neuroticism and pain intensity/bother, and fully mediated relationships between neuroticism and anticipatory anxiety. These data suggest that, at least in children, neuroticism may be best understood as a vulnerability factor for elevated pain responses, especially when coupled with a fear of bodily sensations.

Elevated pain sensitivity in chronic pain patients at risk for opioid misuse

This study employed quantitative sensory testing (QST) to evaluate pain responses in chronic spinal pain patients at low risk and high risk for opioid misuse, with risk classification based on scores on the Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R). Patients were further subgrouped according to current use of prescription opioids. Of the 276 chronic pain patients tested, approximately 65% were taking opioids; a median split was used to further categorize these patients as being on lower or higher doses of opioids. The high-risk group (n = 161) reported higher levels of clinical pain, had lower pressure and thermal pain thresholds at multiple body sites, had lower heat pain tolerance, and rated repetitive mechanical stimuli as more painful relative to the low-risk group (n = 115; P's < .01). In contrast, QST measures did not differ across opioid groups. Multiple linear regression analysis suggested that indices of pain-related distress (ie, anxiety and catastrophizing about pain) were also predictive of hyperalgesia, particularly in patients taking opioids. Collectively, regardless of opioid status, the high-risk group was hyperalgesic relative to the low-risk group; future opioid treatment studies may benefit from the classification of opioid risk, and the examination of pain sensitivity and other factors that differentiate high- and low-risk groups.

PERSPECTIVE

This study demonstrates that chronic spinal pain patients at high risk for misuse of prescription opioids are more pain-sensitive than low-risk patients, whether or not they are currently taking opioids. Indices of pain-related distress were important predictors of pain sensitivity, particularly among those patients taking opioids for pain.