Negative affect and sensitization to pain

Mindfulness-Based Intervention Effect on the Psychophysiological Marker of Self-Regulation in Women With Endometriosis-Related Chronic Pain

Endometriosis is a gynecological disease that involves a broad biopsychosocial compromise with the potential to create a negative vicious cycle. Despite the complexity of factors influencing women's improvement, most interventions investigated target just the peripheral nociceptive sources of endometriosis-related pain. An alternative is intervening in self-regulation, which can potentially influence multiple domains of the illness experience. The present study examines the effect of a brief Mindfulness-Based Intervention (bMBI) on attention and autonomic nervous system regulation in women with endometriosis-related pain. Also, explore the interaction between these self-regulation domains and the affective pain dimension. An exploratory analysis of the secondary outcomes of a pilot randomized controlled trial was performed. The vagally-mediated Heart Rate Variability (vmHRV) at rest, cognitive stress, and recovery was employed to measure autonomic regulation. The Flanker and Stroop tasks were used to estimate the attention domains. Results showed that bMBI (n = 26) significantly improved Flanker accuracy and Flanker and Stroop reaction time compared to the control group (n = 28). bMBI significantly increased vmHRV at rest and recovery after cognitive stress. Attention mediated the bMBI effect on affective pain improvement. Results suggest that bMBI improves self-regulation domains with the potential to develop a broad biopsychosocial benefit in the endometriosis context. PERSPECTIVE: This article demonstrates the positive impact of a brief Mindfulness-Based Intervention on attention and parasympathetic regulation in women suffering from endometriosis-related pain. This mindfulness-induced self-regulation improvement can benefit affective pain and potentially multiple psychophysiological processes relevant to endometriosis.

Power of narrative: a case study about documenting private insightful experiences while dealing with pain and associated disability

Objective

People adjusting to living with a chronic disability, such as chronic pain, seek support and resources from societal systems, including health systems, to help them cope with this reality. This case study describes the use of a digital health platform designed to help in that quest.

Method

MyHealthMyRecord (MHMR), is being developed to record, register and curate personal private experiences of a chronic condition. MHMR allows users to record and log short (30-90s) personal and private audio-videos of their accommodation-seeking journey in a way that can be encrypted, registered, curated and shared privately. This case study describes the use of a prototype version of the platform by a participant co-designer who experienced a sudden onset of a chronic pain condition, of undetermined origin. System use began three months after the onset of the condition and just after being discharged from several months of hospitalization without any definitive diagnosis.

Result

During a three-month period, 65 short unstructured contributions were authored and logged. This paper presents a qualitative analysis of that content. The clips used various communication styles that documented experiences, concerns, issues, positive and negative interactions and pain episodes. Using thematic analysis with open coding, three domains (person-facing, accessibility and system-facing) and eight themes (pain, joy, therapy, environmental, recommendations, technical, culture and communication) were identified. Comments about pain, stress, etc., were the most common and occurred in 75% of all videos while technical and therapy/physio related comments were the fewest and occurred in 3 and 9% of the videos, respectively.

Conclusion

We conclude that it is possible to create recordings of events, thoughts, reflections and issues on different aspects affecting an individual's health and well-being impact, including effects of the chronic condition as well as tangential outcomes such as accessibility (or lack of it), using MHMR over a longer period of time. The next steps will be to develop functionality to annotate the recordings, automatically analyze and summarize collections of recordings to make them consumable, useful and understandable to the individual and others, and then to share those analyses and summaries with others. In addition, evaluate this functionality longitudinally with more users.

Association of parental and adolescent emotion-related factors with adolescent chronic pain behaviors

ABSTRACT

Chronic pain is a prevalent condition in youth, and the pain experience is strongly influenced by emotional processes. Studying emotion variability and regulation (ER) may help better understand pain behavior. As the development of emotion-related abilities predominantly takes place in the family context, examining ER within parent-adolescent dyads is important. We set out to test the association of parent and adolescent ER and adolescent emotional variability with adolescent pain behavior (ie, pain interference, activity avoidance, and activity engagement). A sample of 56 adolescents (Mage = 14.5, 85.7% women) with chronic pain and one of their parents (92.9% mothers) participated in this study. Adolescents completed baseline measures of average pain intensity, ER, and mean positive and negative affect. Furthermore, adolescents completed an electronic diary for 14 consecutive days, reporting on emotional state, activity avoidance, activity engagement, and pain interference. Parents completed measures of ER and their own history of pain. We performed a variable selection procedure, the least absolute shrinkage and selection operator method, to determine important predictors of adolescent pain behavior. Adolescent high positive affect was associated with more activity engagement, less pain interference, and less activity avoidance, indicating that positive affect might enhance the willingness to engage in activities in the presence of pain. Adolescent ER strategy emotional reappraisal and parents' own history of pain were predictors of less activity engagement. Parent ER was not related to adolescent ER. In conclusion, our results highlight the potential of enhancing positive affect as an intervention target for chronic pain.

Health sensitivity in the daily lives of younger and older adults: correlates and longer-term change in health

OBJECTIVES

How susceptible older adults' affect is to fluctuations in health (i.e., health sensitivity) indicates how well they adapt to everyday health challenges. Theory and evidence are inconsistent as to whether older adults are more or less health sensitive than younger adults. The role of health burden as correlate and outcome of health sensitivity and age differences therein is also unclear. We thus move the study of health sensitivity ahead from longitudinal inquiry to examine age differences, the role of health burden, and long-term implications of daily life health sensitivitMethods: We use data from COGITO where 101 younger adults (M_age = 25; range = 20-31) and 103 older adults (M_age = 71; range = 65-80) gave daily reports of physical symptoms and positive and negative affect during a ∼100-day micro-longitudinal phase, as well as reports of trait-level health two years before and after.

RESULTS

Extending earlier reports, older age and higher health burden were (independently) associated with lower health sensitivity in positive but not negative affect. Health sensitivity was unrelated to long-term changes in health burden.

CONCLUSION

We take our findings to indicate successful aging (older adults are not more emotionally vulnerable to health issues) and discuss habituation as a process underlying how age and health burden may reduce health sensitivity.

The Effect of Improving Preoperative Sleep Quality on Perioperative Pain by Zolpidem in Patients Undergoing Laparoscopic Colorectal Surgery: A Prospective, Randomized Study

Methods

A prospective, randomized study was conducted with 88 patients undergoing laparoscopic colorectal surgery. The experimental group (S group, n = 44) was given 10 mg of zolpidem tartrate one night before the surgical procedure, while no medication was given to the control group (C group, n = 44). The primary outcome was the intraoperative remifentanil consumption. Sufentanil consumption, average patient-controlled analgesia (PCA) effective press times, the visual analog scale (VAS) scores, and incidences of postoperative nausea and vomiting (PONV) were recorded at 6 h (T1), 12 h (T2), and 24 h (T3) postoperatively.

Results

The intraoperative remifentanil consumption was significantly lower in the S group than that in the C group (p < 0.01). Sufentanil consumption at 6 h and 12 h postoperatively was significantly lower in the S group than that in the C group (p < 0.05); average PCA effective press times and VAS scores, at 6 h and 12 h postoperatively, were significantly lower in the S group than those in the C group (p < 0.01); differences between groups 24 h postoperatively were not significant. No significant between-group difference was noted in the incidence of nausea and vomiting.

Conclusion

Improving patients' sleep quality the night before surgical procedure by zolpidem can decrease the usage of intraoperative analgesics and reduce postoperative pain.

Development and validation of the Brief Assessment of Distress about Pain

BACKGROUND

The experience of pain is a complex interaction of somatic, behavioural, affective and cognitive components. Negative psychological states (e.g., anxiety, fear and depression) are intertwined with pain and contribute to poorer outcomes for individuals suffering from chronic and acute pain by exacerbating the overall experience of pain and leading to increased dysfunction, disability, and distress. A need exists for efficient assessment of aversive emotional states that are associated with pain.

METHODS

A multistage developmental process included expert judges, two undergraduate samples, and a chronic pain patient sample. The 4-item Brief Assessment of Distress about Pain (BADP) scale was developed to assess anxiety, fear, and depression related to pain, as well as an overall evaluation of distress about pain.

RESULTS

Principal components analyses indicated that the BADP consisted of one factor. Inter-scale correlation coefficients revealed that the BADP was highly related to other measures that assess similar constructs, suggesting evidence for convergent validity. Intra-scale correlation coefficients indicated that the items of the BADP were only moderately associated with each other. Findings also supported evidence for discriminative validity, test-retest reliability, and internal consistency of the BADP.

CONCLUSIONS

The BADP has good psychometric properties as a measure of negative affectivity related to pain. The scale's single negative affectivity item may be useful for screening. The BADP helps address a gap in the literature with regard to a brief measure assessing fear, anxiety, depression, and negative affect in relation to pain. Demonstrated utility in a patient sample indicates the measure is suitable for further clinical study.

SIGNIFICANCE

The BADP provides an efficient, psychometrically-supported means to assess affective distress (i.e., anxiety, fear, depression, and negative affect) associated with pain.

Inducing positive emotions to reduce chronic pain: a randomized controlled trial of positive psychology exercises

PURPOSE

Positive emotions have been found to be analgesic and can be induced by positive psychology exercises. This study tested if positive psychology exercises provide beneficial effects on pain, responses to pain, physical (pain interference), and emotional function.

METHODS

Randomized parallel-group controlled single-blinded superiority-trial including community-dwelling individuals with chronic pain secondary to spinal cord injury. Participants in the intervention group were instructed to practice 4 personalized positive psychology exercises for 8 weeks. Participants in the control group were asked to be mindful and write about current life events.

RESULTS

108 (64%) completed the study. At post-treatment, the intervention participants reported significant reductions in pain intensity and improvements in pain catastrophizing and pain control, relative to baseline. Both groups reported significant decreases in pain interference and negative emotions. Significant between-group differences emerged for pain intensity at post-treatment. At 3-months follow-up, improvements maintained for the intervention group and improvements in positive emotions reached statistical significance. Between-group differences were identified for pain intensity at post-treatment.

CONCLUSION

Positive psychology exercises represent a potential effective complementary treatment that result in benefits on pain which can be readily implemented into daily living. Trials designed with an inactive control condition should be conducted to further address efficacy.

TRIAL REGISTRATION

Swiss ethics committee (EKNZ 2014-317)/clinicaltrials.gov (NCT02459028) Registration date: Ethics approval 25.10.2014/Study start date: May 2015 URL of the record: https://clinicaltrials.gov/ct2/show/NCT02459028?term=NCT02459028&cntry=CH&draw=2&rank=1IMPLICATIONS FOR REHABILITATIONPain engenders negative emotions (e.g., fear, anger, sadness) which can negatively affect psychological, social, and physical function.Positive emotions have been found to be analgesic and can be induced by practicing positive psychology exercises.The findings of the current randomized controlled trial provide support for practicing positive psychology exercises (beyond the effects of pain medication intake), in particular on the reduction of pain intensity, but also in improving pain catastrophizing and pain control.The majority of the positive psychology exercises are brief and self-administered positive activities that have no known negative side effects nor financial cost, can be tailored to a person's preferences in activities and can be readily implemented into daily living with chronic pain, complementing standard treatment of pain.

Are Cognitive Load and Focus of Attention Differentially Involved in Pain Management: An Experimental Study Using a Cold Pressor Test and Virtual Reality

Objective

The aim of this study is to assess whether distraction (lack of attentional focus) and attention (cognitive load) are differentially involved in the analgesic effect of virtual reality (VR) immersions during a cold pressor test (CPT).

Methods

Thirty-one participants were randomly assigned to four experimental conditions (high and low cognitive load, attention with or without a reminder of the pain stimuli) and performed three CPTs. Pain was assessed based on the duration of the CPT (pain tolerance), a visual analog rating scale of perceived pain intensity during the CPT and the subjective pain scale of the Short form McGill Pain Questionnaire (SF-MPQ).

Results

The statistical analyses revealed that VR immersions were associated with less pain compared to the baseline (all p <0.001), but for the experimental manipulations, only the conditions where there was an increase in cognitive load (ie, from low cognitive load at Immersion 1 to high cognitive load at Immersion 2) were effective for increasing pain tolerance (significant Time X Conditions interaction). The interactions were not significant for pain intensity assessed with the VAS or the SF-MPQ.

Conclusion

The results suggest that increases in cognitive load play an important role in the analgesic effect of VR immersion, although the combination of attentional focus and cognitive load may be important. Suggestions are given for designing a replication study.

Transcutaneous Electrical Stimulation on the Submental Area: The Relations of Biopsychological Factors with Maximum Amplitude Tolerance and Perceived Discomfort Level

Transcutaneous electrical stimulation (TES) is a frequently used adjunctive modality in dysphagia rehabilitation. Stimulating deeper swallowing muscles requires higher TES amplitude. However, TES amplitude is limited by maximum amplitude tolerance (MAT). Previous studies have reported high interindividual variability regarding MAT and perceived discomfort. This variability might be one of the potential reasons of conflicting outcomes in TES-based swallowing studies. MAT and perceived discomfort are influenced by a variety of biopsychological factors. The influence of these factors related to swallow applications is poorly understood. This study explored the relation of biopsychological factors with MAT and perceived discomfort related to TES in the submental area. A convenience sample of thirty community-dwelling older adults between 60 and 70 years of age provided data for this study. Gender, submental adipose tissue thickness, perceptual pain sensitivity, and pain-coping strategies were evaluated for each subject. Subsequently, MAT and perceived discomfort level were determined using TES on the submental area. Relation of different biopsychological variables with MAT and discomfort level was examined using Pearson and Spearman correlation, and Mann-Whitney U test. Results indicated that neither gender nor adipose thickness was related to MAT and perceived discomfort. Among studied pain-coping strategies, catastrophizing was significantly related to MAT(r = - 0.552, p < .002). Distraction was significantly related to perceived discomfort level (r = - 0.561, p < 0.002). Given the negative impact of pain catastrophizing on MAT and the positive impact of distraction on perceiving discomfort, these coping strategies should be considered as amplitude-limiting and discomfort-moderating factors in TES-based dysphagia rehabilitation.

Idiographic measurement of depressive thinking: development and preliminary validation of the Sentence Completion Test for Chronic Pain (SCP)

Background and aims Depression is a common feature of chronic pain, but there is only limited research into the content and frequency of depressed cognitions in pain patients. This study describes the development of the Sentence Completion Test for Chronic Pain (SCP), an idiographic measure for assessing depressive thinking in chronic pain patients. The sentence completion task requires participants to finish incomplete sentences using their own words to a set of predefined stems that include negative, positive and neutral valenced self-referenced words. In addition, the stems include past, future and world stems, which reflect the theoretical negative triad typical to depression. Complete responses are coded by valence (negative, positive and neutral), pain and health-related content. Methods A total of 89 participants were included in this study. Forty seven adult out-patients formed the depressed pain group and were compared to a non-clinical control sample of 42 healthy control participants. This study comprised several phases: (1) theory-driven generation of coding rules; (2) the development of a coding manual by a panel of experts (3) comparing reliability of coding by expert raters without the use of the coding manual and with the use of the coding manual; (4) preliminary analyses of the construct validity of the SCP. The internal consistency of the SCP was tested using the Kuder-Richardson coefficient (KR-20). Inter-rater agreement was assessed by intra-class correlations (ICC). The content and construct validity of the SCP was investigated by correlation coefficients between SCP negative completions, the Hospital Anxiety and Depression Scale (HADS) depression scores and the number of symptoms on the Structured Clinical Interview for DSM-IV-TR (SCID). Results As predicted for content validity, the number of SCP negative statements was significantly greater in the depressed pain group and this group also produced significantly fewer positive statements, compared to the healthy control group. The number of negative pain completions and negative health completions was significantly greater in the depressed pain group. As expected, in the depressed pain group, the correlation between SCP negatives and the HADS Depression score was r=0.60 and the correlation between SCP negatives and the number of symptoms on the SCID was r=0.56. Conclusions The SCP demonstrated good content validity, internal consistency and inter-rater reliability. Implications Uses for this measure, such as complementing questionnaire measures by an idiographic assessment of depressive thinking and generating hypotheses about key problems within a cognitive-behavioural case-formulation, are suggested.

Gaining insights on the influence of attention, anxiety, and anticipation on pain perception

Purpose

This article highlights the influence of attention and pain anticipation on pain attenuation. Pain-related trait anxiety was found to moderate the effect that attention strategies impose on pain perception. This article may contribute to clinical treatments quality, where pain attenuation effect is desired.

Participants and methods

One hundred seven participants, comprising of 72 (67%) females and 35 (33%) males between the age of 17 and 48 (M=22.6, SD =4.36), were used in the analysis. The current study measured the effect of pain anticipation and attention on three aspects of pain perception: threshold, tolerance, and perceived pain intensity. Pain anticipation was manipulated by varying the amount of information given to participants about a future pain stimulus. Attention was manipulated through a sensory focusing task and a distraction task. Participants were randomized into 1) InfoControl group with distraction task trial (n=30), 2) InfoControl group with attention to pain trial (n=26), 3) InfoExtra group with distraction task trial (n=26), or 4) InfoExtra group with attention to pain trial (n=25). The pain stimulus was delivered in a form of heat. The moderating effects of pain-related trait anxiety on these variables were also investigated using Pain Anxiety Symptom Scale Short Form.

Results

Two structural equation models revealed that anticipation is not a predictor of pain perception and neither did it interact with pain-related trait anxiety. However, attention strategies do significantly relate to pain perception. Furthermore, pain-related anxiety was a significant moderator of attention and pain attenuation. These findings imply that the effectiveness of attention strategies in attenuating pain is affected by individuals’ pain-related trait anxiety.

Conclusion

The results suggest the importance of appointing the appropriate attention strategy to different individuals with varying level of trait anxiety. Future explorations are necessary to develop a more specific understanding on the nature of information and distractions on pain perception.

Social support, social undermining, and acute clinical pain in women: Mediational pathways of negative cognitive appraisal and emotion

Women may be disproportionately vulnerable to acute pain, potentially due to their social landscape. We examined whether positive and negative social processes (social support and social undermining) are associated with acute pain and if the processes are linked to pain via negative cognitive appraisal and emotion (pain catastrophizing, hyperarousal, anger). Psychosocial variables were assessed in inner-city women (N = 375) presenting to an Emergency Department with acute pain. The latent cognitive-emotion variable fully mediated social undermining and support effects on pain, with undermining showing greater impact. Pain may be alleviated by limiting negative social interactions, mitigating risks of alternative pharmacological interventions.

Machine-learning-derived classifier predicts absence of persistent pain after breast cancer surgery with high accuracy

Background

Prevention of persistent pain following breast cancer surgery, via early identification of patients at high risk, is a clinical need. Supervised machine-learning was used to identify parameters that predict persistence of significant pain.

Methods

Over 500 demographic, clinical and psychological parameters were acquired up to 6 months after surgery from 1,000 women (aged 28–75 years) who were treated for breast cancer. Pain was assessed using an 11-point numerical rating scale before surgery and at months 1, 6, 12, 24, and 36. The ratings at months 12, 24, and 36 were used to allocate patents to either “persisting pain” or “non-persisting pain” groups. Unsupervised machine learning was applied to map the parameters to these diagnoses.

Results

A symbolic rule-based classifier tool was created that comprised 21 single or aggregated parameters, including demographic features, psychological and pain-related parameters, forming a questionnaire with “yes/no” items (decision rules). If at least 10 of the 21 rules applied, persisting pain was predicted at a cross-validated accuracy of 86% and a negative predictive value of approximately 95%.

Conclusions

The present machine-learned analysis showed that, even with a large set of parameters acquired from a large cohort, early identification of these patients is only partly successful. This indicates that more parameters are needed for accurate prediction of persisting pain. However, with the current parameters it is possible, with a certainty of almost 95%, to exclude the possibility of persistent pain developing in a woman being treated for breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4841-8) contains supplementary material, which is available to authorized users.

Associations between pain intensity and urge to smoke: Testing the role of negative affect and pain catastrophizing

BACKGROUND

Cigarette smokers are more likely to experience pain than nonsmokers, and experimental research indicates that pain is a potent motivator of smoking. Urge to smoke is a predictor of early relapse, yet associations between pain and urge to smoke have yet to be tested among daily smokers. This study aimed to conduct the first crosssectional test of associations between current pain intensity and urge to smoke, and to test the role of negative affect and pain catastrophizing in relations between pain intensity and urge to smoke.

METHODS

Participants (N = 229, 42.4% Female, 38.9% black/African American, Mcpd = 21.9) were recruited for a laboratory study of pain and smoking, and these data were collected at the baseline session. Data were analyzed using a series of regressions and conditional process models.

RESULTS

Current pain intensity was positively associated with urge to smoke, and urge to smoke for the relief of negative affect. There was an indirect association via state negative affect, such that pain intensity was positively associated with negative affect, which in turn was associated with greater urge to smoke. Further, positive associations between pain intensity and urge to smoke were only evident among smokers who endorsed low (vs high) levels of catastrophizing.

CONCLUSIONS

These findings contribute to an emerging literature indicating that pain and related constructs are relevant to the maintenance of tobacco smoking. Future research should examine how painrelevant cognitive-affective factors may influence associations between the experience of pain and motivation to smoke tobacco.

Cognitive and affective mechanisms of pain and fatigue in multiple sclerosis

OBJECTIVE

To examine the extent to which pain catastrophizing, fatigue catastrophizing, positive affect, and negative affect simultaneously mediated the associations between common symptoms of multiple sclerosis (MS; i.e., pain, fatigue) and impact on daily life, depressive symptoms, and resilience.

METHOD

Participants were community-dwelling adults with MS (N = 163) reporting chronic pain, fatigue, and/or moderate depressive symptoms. Multiple mediation path analysis was used to model potential mediators of pain and fatigue separately, using baseline data from a randomized controlled trial comparing two symptom self-management interventions.

RESULTS

In the pain model, pain catastrophizing was a mediator of pain intensity with pain interference and depression. Negative affect was a mediator of pain intensity with depression and resilience. In the fatigue model, fatigue catastrophizing was a mediator of fatigue intensity with fatigue impact and depression. Positive affect was a mediator of fatigue intensity with depression and resilience.

CONCLUSIONS

These findings provide preliminary support for the presence of differential effects of cognitive-affective mediators and suggest potential targets for psychological interventions based on an individual's clinical presentation. The differential mediating effects also support the inclusion of both positive and negative aspects of psychological health in models of pain and fatigue, which would not be otherwise apparent if negative constructs were examined in isolation. To our knowledge, this is the first study to utilize a multivariate path analysis approach to examine cognitive-affective mediators of pain and fatigue in MS, while also examining positive and negative constructs concurrently. (PsycINFO Database Record

Alexithymia, not fibromyalgia, predicts the attribution of pain to anger-related facial expressions

BACKGROUND

Fibromyalgia (FM) is a syndrome characterized by chronic, widespread musculoskeletal pain, occurring predominantly in women. Previous studies have shown that patients with FM display a pattern of selective processing or cognitive bias which fosters the encoding of pain-related information. The present study tested the hypothesis of an increased attribution of pain to facial expressions of emotions (FEE), in patients with FM. As previous studies have shown that alexithymia influences the processing of facial expressions, independent of specific clinical conditions, we also investigated whether alexithymia, rather than FM per se, influenced attribution of pain to FEE.

METHODS

One hundred and twenty-three women (41 with FM, 82 healthy controls, HC) were enrolled in this cross-sectional case-control study. We adopted two pain-attribution tasks, the Emotional Pain Estimation and the Emotional Pain Ascription, both using a modified version of the Ekman 60 Faces Test. Psychological distress was assessed using the Hospital Anxiety and Depression Scale, and alexithymia was assessed using the Toronto Alexithymia Scale.

RESULTS

Patients with FM did not report increased attribution of pain to FEE. Alexithymic individuals demonstrated no specific problem in the recognition of basic emotions, but attributed significantly more pain to angry facial expression.

LIMITATIONS

Our study involved a relatively small sample size. The use of self-reported instruments might have led to underestimation of the presence of frank alexithymia in individuals having borderline cut-off scores.

CONCLUSIONS

Alexithymia, rather than FM per se, plays a key role in explaining the observed differences in pain attribution to anger-related facial expressions.

Stress and Addiction: When a Robust Stress Response Indicates Resiliency

OBJECTIVE

Stress reactivity research has traditionally focused on the idea that exaggerated responses to stress may have adverse effects on health. Accumulating evidence suggests that attenuated responses to stress and delayed recovery may also be problematic.

METHODS

This review focuses on the role of the stress response of the hypothalamic-pituitary-adrenocortical axis, the endogenous opioid system, and the cardiovascular system in hypertension, pain perception, and addictive behaviors. Results from multiple methods of assessment and stress paradigms conducted in our laboratory over the past two decades are integrated with research from other investigators and with existing theories.

RESULTS

Research indicates that exaggerated biological and physiological responses to stress and attenuated pain perception are associated with hypertension and risk for cardiovascular diseases. This research complements work linking reduced stress responses with enhanced pain sensitivity and discomfort. Multiple studies have also demonstrated that an attenuated stress response is linked to exacerbation of withdrawal symptoms and relapse in nicotine addiction. Evidence indicates important moderators (i.e., sex, personality traits, and early life adversity) and hypothalamic-pituitary-adrenocortical- and endogenous opioid system-related mechanisms in the altered response to stress. I integrate these findings in a conceptual model emphasizing that robust stress responses in the context of addiction and relapse should be considered as a marker of resiliency.

CONCLUSIONS

A blunted stress response may indicate long-term physiological dysregulation that could usher harmful consequences for cardiovascular disease, pain perception, and addictive disorders. The impact of dysregulation is influenced by multiple individual and situational factors that should be considered in evaluating the clinical significance of stress response dysregulation.

Pain catastrophizing mediates the relationship between trait happiness and depressive symptoms in individuals with current pain

OBJECTIVE

There is an extensive relationship between chronic pain and depression; however, there is less research examining whether pain-specific factors, such as pain intensity, predict depression, above and beyond the role of normative factors, such as positive emotions. The current study characterized the independent contributions of pain intensity, pain catastrophizing, and a trait measure of happiness to self-rated depressive symptoms.

METHODS

We recruited and enrolled 70 volunteers across 3 groups of participants: two groups of patients with current low back pain (one group on opioids and one group opioid-naïve), and individuals in a methadone maintenance treatment program.

RESULTS

Of note, participants reporting concurrent opioid use reported significantly higher levels of depressive symptomatology, although study groups did not differ on any other clinical variables. In our path model, we failed to find direct relationships between pain (intensity or duration) and either trait happiness or depressive symptoms (p > .05). However, our analysis did reveal that individuals with chronic back pain who reported higher levels of trait happiness reported lower levels of depressive symptomatology; this effect was significantly mediated by lower levels of pain catastrophizing (standardized ab = -.144, p = .002).

CONCLUSION

Our analysis suggests that trait happiness, while unrelated to ongoing pain, may predict a decreased vulnerability to depressive symptoms in individuals with chronic pain, which may operate via lower levels of pain catastrophizing.

Can positive affect attenuate (persistent) pain? State of the art and clinical implications

Purpose of Review

Pain is an intense experience that can place a heavy burden on peoples’ lives. The identification of psychosocial risk factors led to the development of effective pain treatments. However, effect sizes are modest. Accumulating evidence suggests that enhancing protective factors might also impact on (well-being despite) pain. Recent findings on positive affect (interventions) towards pain-related outcomes will be reviewed, and new avenues for treatment of persistent pain will be discussed.

Recent Findings

Positive affect significantly attenuates the experience of pain in healthy and clinical populations. Positive affect interventions effectively reduce pain sensitivity and bolster well-being despite pain. Through both psychological and (neuro-)biological pathways, but also through its effect on central treatment processes such as inhibitory learning, positive affect can optimize the efficacy of existing treatments.

Summary

Comprehensive understanding of the unique roles and dynamic interplay of positive and negative affect in moderating pain may optimize the treatment of (persistent) pain.

Role of the Attachment Style in Determining the Association Between Headache Features and Psychological Symptoms in Migraine Children and Adolescents. An Analytical Observational Case-Control Study

OBJECTIVE

We aimed to study the role of attachment style on headache severity and psychological symptoms in migraineurs children/adolescents. Moreover, we investigated the association between attachment style, migraine severity, and psychological symptoms.

BACKGROUND

Attachment theory suggests that early interpersonal relationships may be important determinants of psychopathology and pain management. In particular, individuals with insecure attachment styles have been shown to experience more pain than people with secure attachment style. Few studies focused on headache and data on attachment style in pediatric headache are scarce.

METHODS

We studied 90 migraineurs (mean age 12.2 ± 2.6 years; female: 54, male: 36). Patients were divided in two groups according to headache attack frequency: (1) high frequency (HF) patients, having from weekly to daily episodes and (2) low frequency (LF) patients, showing ≤3 episodes per month. According to headache attack intensity, patients were classified in two groups: (1) mild pain (MP), allowing the patient to continue his/her daily activities and (2) severe pain (SP), leading to interruption of patient activities or forcing the child to go to bed. The psychological screening was assessed by SAFA Anxiety, Depression, and Somatization questionnaires. Attachment style was measured by the semi-projective test Separation Anxiety Test. Patients were divided into "secure," "avoidant," "ambivalent," and "disorganized/confused" attachment patterns.

RESULTS

We found a significant relationship between the attachment style and migraine features. The ambivalent attachment was the most common style among patients reporting high attack frequency (51%) and severe pain intensity (50%). Anxiety (SAFA-A Tot: F = 23.3, P < .001), depression (SAFA-D Tot: F = 11.8, P < .001), and somatization (SAFA-S Tot: F = 10.1, P < .001) were higher in patients with ambivalent attachment style. Moreover, our results showed an association between high attack frequency and high anxiety levels, in children with ambivalent attachment style (F = 6.7, P < .002).

CONCLUSIONS

Ambivalent attachment style may be a common vulnerability factor that impacts on pain severity, anxiety, depression, and somatization symptoms in young migraineurs. In particular, the present study provides the first evidence of the role of insecure attachment on the relationship between pain severity and psychological symptoms in migraine children.

Depressive Symptoms and Momentary Mood Predict Momentary Pain Among Rheumatoid Arthritis Patients

BACKGROUND

Although a relationship between mood and pain has been established cross-sectionally, little research has examined this relationship using momentary within-person data.

PURPOSE

We examined whether baseline depressive symptoms and within-person levels of negative and positive mood predicted momentary pain among 31 individuals with rheumatoid arthritis (RA).

METHODS

Depressive symptomatology was measured at baseline. Mood and RA symptoms were self-reported via ecological momentary assessment five times a day for seven consecutive days. Analyses controlled for gender, age, weekend day, time of day, and experiences of stress.

RESULTS

Greater momentary positive mood was associated with less momentary pain and fewer arthritis-related restrictions; negative mood was associated with more restrictions. Greater depressive symptomatology also predicted more pain and restrictions, an effect which was not accounted for by mood.

CONCLUSIONS

Results suggest that both depression and mood are uniquely associated with momentary pain; as such, multi-component interventions may provide optimal disease management.

Decoding the perception of endogenous pain from resting-state MEG

Decoding the neural representations of pain is essential to obtaining an objective assessment as well as an understanding of its underlying mechanisms. The complexities involved in the subjective experience of pain make it difficult to obtain a quantitative assessment from the induced spatiotemporal patterns of brain activity of high dimensionality. Most previous studies have investigated the perception of pain by analyzing the amplitude or spatial patterns in the response of the brain to external stimulation. This study investigated the decoding of endogenous pain perceptions according to resting-state magnetoencephalographic (MEG) recordings. In our experiments, we applied a beamforming method to calculate the brain activity for every brain region and examined temporal and spectral features of brain activity for predicting the intensity of perceived pain in patients with primary dysmenorrhea undergoing menstrual pain. Our results show that the asymmetric index of sample entropy in the precuneus and the sample entropy in the left posterior cingulate gyrus were the most informative characteristics associated with the perception of menstrual pain. The correlation coefficient (ρ=0.64, p<0.001) between the predicted and self-reported pain scores demonstrated the high prediction accuracy. In addition to the estimated brain activity, we were able to predict accurate pain scores directly from MEG channel signals (ρ=0.65, p<0.001). These findings suggest the possibility of using the proposed model based on resting-state MEG to predict the perceived intensity of endogenous pain.

Circumplex Model of Affect: A Measure of Pleasure and Arousal During Virtual Reality Distraction Analgesia

OBJECTIVE

Immersive virtual reality (VR) distraction provides clinically effective pain relief and increases subjective reports of "fun" in medical settings of procedural pain. The goal of this study was to better describe the variable of "fun" associated with VR distraction analgesia using the circumplex model (pleasure/arousal) of affect.

MATERIALS AND METHODS

Seventy-four healthy volunteers (mean age, 29 years; 37 females) received a standardized, 18-minute, multimodal pain sequence (alternating thermal heat and electrical stimulation to distal extremities) while receiving immersive, interactive VR distraction. Subjects rated both their subjective pain intensity and fun using 0-10 Graphic Rating Scales, as well as the pleasantness of their emotional valence and their state of arousal on 9-point scales.

RESULTS

Compared with pain stimulation in the control (baseline, no VR) condition, immersive VR distraction significantly reduced subjective pain intensity (P < 0.001). During VR distraction, compared with those reporting negative affect, subjects reporting positive affect did so more frequently (41 percent versus 9 percent), as well as reporting both greater pain reduction (22 percent versus 1 percent) and fun scores (7.0 ± 1.9 versus 2.4 ± 1.4). Several factors-lower anxiety, greater fun, greater presence in the VR environment, and positive emotional valence-were associated with subjective analgesia during VR distraction.

CONCLUSIONS

Immersive VR distraction reduces subjective pain intensity induced by multimodal experimental nociception. Subjects who report less anxiety, more fun, more VR presence, and more positive emotional valence during VR distraction are more likely to report subjective pain reduction. These findings indicate VR distraction analgesia may be mediated through anxiolytic, attentional, and/or affective mechanisms.

Psychiatric Comorbidity Is Associated Prospectively with Diminished Opioid Analgesia and Increased Opioid Misuse in Patients with Chronic Low Back Pain

BACKGROUND

Opioids are frequently prescribed for chronic low back pain (CLBP), but there are little prospective data on which patient subgroups may benefit. Psychiatric comorbidity, such as high levels of depression and anxiety symptoms (termed comorbid negative affect [NA]), is a common presentation and may predict diminished opioid analgesia and/or increased opioid misuse.

METHODS

The authors conducted a 6½-month prospective cohort study of oral opioid therapy, with an active drug/placebo run-in period, in 81 CLBP patients with low, moderate, and high levels of NA. Treatment included an opioid titration phase with a prescribing physician blinded to NA group assignment and a 4-month continuation phase, during which subjects recorded daily pain levels using an electronic diary. The primary outcome was the percent improvement in average daily pain, summarized weekly.

RESULTS

There was an overall 25% dropout rate. Despite the high NA group being prescribed a higher average daily dose of morphine equivalents, linear mixed model analysis revealed that the 24 study completers in each of the high NA and low NA groups had an average 21 versus 39% improvement in pain, respectively (P < 0.01). The high NA group also had a significantly greater rate of opioid misuse (39 vs. 8%, P < 0.05) and significantly more and intense opioid side effects (P < 0.01).

CONCLUSIONS

These results indicate that the benefit and risk considerations in CLBP patients with high NA versus low NA are distinctly different. Thus, NA is an important phenotypic variable to characterize at baseline, before deciding whether to prescribe opioids for CLBP.

The role of positive affect in pain and its treatment

OBJECTIVE

This narrative review summarizes and integrates the available literature on positive affect (PA) and pain to: (1) provide a brief overview of PA and summarize the key findings that have emerged in the study of PA and pain; (2) provide a theoretical foundation from which to understand how PA operates in the context of chronic pain (CP); and (3) highlight how the prevailing psychosocial treatments for CP address PA in the therapeutic context, and offer suggestions for how future treatment development research can maximize the benefit of PA for patients with CP.

RESULTS

In experimental studies, the evidence suggests PA is analgesic. In clinical studies, the association of PA and pain is dynamic, time variant, and may be best considered in context of its interacting role with negative affect.

DISCUSSION

We offer an "upward spiral" model of PA, resilience and pain self-management, which makes specific predictions that PA will buffer maladaptive cognitive and affective responses to pain, and promote active engagement in valued goals that enhance CP self-management.

Measurement considerations for achieving equity in research inclusion for transition-aged youth with disabilities

Measuring health for youth with intellectual disabilities (ID) is important for tracking progress toward national health goals. Measures of biophysical and fitness indicators are important but difficult to obtain in youth with ID, particularly in community settings. This paper describes obstacles encountered and strategies used to measure outcomes in a community-based study. Proposed best practices include adaptations in procedures to maximize comprehension; preparation of the environment to provide privacy and predictability; and appropriately sized equipment to obtain accurate readings. Reliable and valid measures, specific to youth with ID, would improve promote research inclusion and reduce health disparities for this population.

Understanding the relationship between smoking and pain

This review provides an overview of evidence regarding several key mechanisms pertinent to understanding the co-occurrence of smoking dependence and pain, both potentially costly conditions, and highlights treatment implications and future research directions. We describe each of pain and smoking dependence and introduce a revised integrative reciprocal model that explains their co-occurrence. We then provide a selective review of evidence pertinent to direct and indirect pathways between variables postulated in the model. We also provide general recommendations for improving assessment and treatment of smokers with clinically significant pain. We conclude with a targeted agenda for future investigation of the co-occurrence of smoking and pain. Empirical efforts directed at testing postulates of the proposed integrative model may yield a better understanding of the nature of the relationship between these prevalent and costly health conditions as well as evidence-based preventive and treatment strategies for people who experience nicotine dependence and pain-related disability.

Nonpharmacologic approaches for pain management during labor compared with usual care: a meta-analysis

OBJECTIVES

To assess the effects of nonpharmacologic approaches to pain relief during labor, according to their endogenous mechanism of action, on obstetric interventions, maternal, and neonatal outcomes.

DATA SOURCE

Cochrane library, Medline, Embase, CINAHL and the MRCT databases were used to screen studies from January 1990 to December 2012.

STUDY SELECTION

According to Cochrane criteria, we selected randomized controlled trials that compared nonpharmacologic approaches for pain relief during labor to usual care, using intention-to-treat method.

RESULTS

Nonpharmacologic approaches, based on Gate Control (water immersion, massage, ambulation, positions) and Diffuse Noxious Inhibitory Control (acupressure, acupuncture, electrical stimulation, water injections), are associated with a reduction in epidural analgesia and a higher maternal satisfaction with childbirth. When compared with nonpharmacologic approaches based on Central Nervous System Control (education, attention deviation, support), usual care is associated with increased odds of epidural OR 1.13 (95% CI 1.05-1.23), cesarean delivery OR 1.60 (95% CI 1.18-2.18), instrumental delivery OR 1.21 (95% CI 1.03-1.44), use of oxytocin OR 1.20 (95% CI 1.01-1.43), labor duration (29.7 min, 95% CI 4.5-54.8), and a lesser satisfaction with childbirth. Tailored nonpharmacologic approaches, based on continuous support, were the most effective for reducing obstetric interventions.

CONCLUSION

Nonpharmacologic approaches to relieve pain during labor, when used as a part of hospital pain relief strategies, provide significant benefits to women and their infants without causing additional harm.

State and trait pain catastrophizing and emotional health in rheumatoid arthritis

BACKGROUND

Pain catastrophizing is a powerful predictor of pain adaptation, and both stable and time-varying aspects may influence overall emotional well-being.

PURPOSE

This study aims to test the independent influences of state and trait pain catastrophizing on the relationship between daily intensity and negative affect, positive affect, and depressive symptoms.

METHODS

Daily diary data were collected for 30 days from a sample of 231 adults with a diagnosis of rheumatoid arthritis.

RESULTS

State pain catastrophizing accounted for a significant proportion of the relationship between daily pain and each of the three examined daily outcomes. Greater trait pain catastrophizing significantly increased the effect of state pain catastrophizing on the relationship between pain intensity and the outcome variables in cross-sectional and time-lagged models.

CONCLUSIONS

The results of the current study indicate that state pain catastrophizing plays a prominent role in the adaptation to daily pain fluctuations, particularly for those with a propensity to catastrophize.

Morning types are less sensitive to pain than evening types all day long

BACKGROUND

Diurnal variations in pain have been observed in experimental protocols, post-surgery states and pathological conditions. Chronotype is considered to have the most profound effect on diurnal variations, and in addition, previous studies suggest that evening types may be more vulnerable to pain than morning types. This study aimed to examine whether or not morning and evening chronotypes differ in terms of their daily levels and diurnal fluctuations of pain sensitivity.

METHODS

A total of 16 morning-healthy and 15 evening-healthy men were selected using the Morningness-Eveningness Questionnaire and underwent nine measurements during 1 day (between 08:15 and 20:15 h), each consisting of five heat stimuli situated at the ventral side of the wrist.

RESULTS

A marked difference between chronotypes was found, with morning types showing less sensitivity to pain than evening types all day long [M = 50.1; standard error (SE) = 1 and M = 47.2; SE = 1, respectively; pain thresholds in centigrade]. Diurnal variations in pain were not statistically significant.

CONCLUSIONS

The results showed that chronotype could be an important factor determining sensitivity to pain, regardless of time of day.

Stress response dysregulation and stress-induced analgesia in nicotine dependent men and women

Alterations in the stress response and endogenous pain regulation mechanisms may contribute directly and indirectly to maintenance of nicotine dependence and relapse. We examined the extent to which nicotine dependence alters endogenous pain regulatory systems, including the hypothalamic-pituitary-adrenocortical axis, cardiovascular activity, and stress-induced analgesia. Smokers and nonsmokers attended a laboratory session that included assessment of hormonal and cardiovascular responses to stress. Smokers smoked at their regular rate prior to the session. The hand cold pressor and heat thermal pain tests were completed twice, once after acute stress (public speaking and math tasks) and the other after rest. While smokers and nonsmokers exhibited significant hormonal and cardiovascular responses to stress, smokers exhibited blunted stress responses relative to nonsmokers. They also exhibited diminished stress-induced analgesia. Results demonstrate altered stress response and diminished stress-induced analgesia among chronic smokers, and suggest that these dysregulated physiological responding may contribute to altered endogenous pain regulation.

Pilot randomized controlled trial of a patient-controlled cognitive-behavioral intervention for the pain, fatigue, and sleep disturbance symptom cluster in cancer

CONTEXT

Pain, fatigue, and sleep disturbance commonly co-occur in patients receiving treatment for advanced cancer.

OBJECTIVES

A pilot randomized controlled trial was conducted to assess initial efficacy of a patient-controlled cognitive-behavioral (CB) intervention for the pain, fatigue, and sleep disturbance symptom cluster.

METHODS

Eighty-six patients with advanced lung, prostate, colorectal, or gynecologic cancers receiving treatment at a comprehensive cancer center were stratified by recruitment clinics (chemotherapy and radiation therapy) and randomized to intervention or control groups. Forty-three patients were assigned to receive training in and use of up to 12 relaxation, imagery, or distraction exercises delivered via an MP3 player for two weeks during cancer treatment. Forty-three patients were assigned to a waitlist control condition for the same two week period. Outcomes included symptom cluster severity and overall symptom interference with daily life measured at baseline (Time 1) and two weeks later (Time 2).

RESULTS

Eight participants dropped out; 78 completed the study and were analyzed (36 intervention and 42 control subjects). Participants used the CB strategies an average of 13.65 times (SD=6.98). Controlling for baseline symptom cluster severity and other relevant covariates, it was found that the symptom cluster severity at Time 2 was lower in the intervention group (M(Adj)=2.99, SE=0.29) than in the waitlist group (M(Adj)=3.87, SE=0.36), F(1, 65)=3.57, P=0.032. Symptom interference with daily life did not differ between groups. No significant adverse events were noted with the CB intervention.

CONCLUSION

Findings suggest that the CB intervention may be an efficacious approach to treating the pain, fatigue, and sleep disturbance symptom cluster. Future research is planned to confirm efficacy and test mediators and moderators of intervention effects.

An everyday phrase may harm your patients: the influence of negative words on pain during venous blood sampling

OBJECTIVE

Venous blood sampling is one of the most common diagnostic medical procedures performed in clinical practice. It has been shown that negatively loaded words may result in negative affective reactions and, consequently, in an increased perception of pain. We aimed to evaluate whether common warnings before venous blood sampling might induce unnecessary pain.

METHODS

We included 100 healthy participants (50 females, 50 males) who were randomized to one of the 2 study groups ("sting" vs. "beware"). Directly before insertion of the needle, the participants were warned with either the word "sting" or "beware." Venous blood sampling was performed according to a standardized protocol. Preinterventional and postinterventional blood pressure and heart rate, as well as pain scores after venous blood sampling, were evaluated.

RESULTS

There were 98 participants, 26.2 ± 3.2 years of age, who were included into the analysis. Participants experienced significantly more pain after having been warned with the word "sting" compared with the word "beware." The numeric rating scale results were 2.7 ± 1.2 versus 1.9 ± 1.1, respectively (P=0.001).

DISCUSSION

Words associated with pain increase the perception of pain during venous blood sampling. Omitting these words may be a simple and essential method by which to avoid unnecessary pain.

Are emotion regulation skills related to adjustment among people with chronic pain, independent of pain coping?

Although emotion regulation capacities have been linked to adjustment among people with chronic pain, researchers have yet to determine whether these capacities are related to functioning independent of established facets of pain coping. The present study was designed to address this gap. A sample 128 Australian adults with chronic pain (44 men, 84 women) completed self-report measures of adjustment (quality of life, negative affect, and pain-related disability), pain coping, and features of emotion regulation (emotion appraisal, perceived efficacy in emotion regulation, emotion utilization). Hierarchical multiple regression analyses indicated that efficacy in emotion regulation was related to quality of life and reduced negative affect even after statistically controlling for effects of other measures of adjustment, pain coping efficacy, and pain coping. Conversely, features of emotion regulation did not improve the prediction model for pain-related disability. Findings suggest emotion regulation capacities may have a unique role in the prediction of specific facets of adjustment among people with chronic pain.

Placebo and other psychological interactions in headache treatment

We present a theory according which a headache treatment acts through a specific biological effect (when it exists), a placebo effect linked to both expectancy and repetition of its administration (conditioning), and a non-specific psychological effect. The respective part of these components varies with the treatments and the clinical situations. During antiquity, suggestions and beliefs were the mainstays of headache treatment. The word placebo appeared at the beginning of the eighteenth century. Controversies about its effect came from an excessive interpretation due to methodological bias, inadequate consideration of the variation of the measure (regression to the mean) and of the natural course of the disease. Several powerful studies on placebo effect showed that the nature of the treatment, the associated announce, the patients' expectancy, and the repetition of the procedures are of paramount importance. The placebo expectancy is associated with an activation of pre-frontal, anterior cingular, accumbens, and periacqueducal grey opioidergic neurons possibly triggered by the dopaminergic meso-limbic system. In randomized control trials, several arms design could theoretically give information concerning the respective part of the different component of the outcome and control the natural course of the disease. However, for migraine and tension type headache attacks treatment, no three arm (verum, placebo, and natural course) trial is available in the literature. Indirect evidence of a placebo effect in migraine attack treatment, comes from the high amplitude of the improvement observed in the placebo arms (28% of the patients). This figure is lower (6%) when using the harder criterium of pain free at 2 h. But these data disregard the effect of the natural course. For prophylactic treatment with oral medication, the trials performed in the last decades report an improvement in 21% of the patients in the placebo arms. However, in these studies the duration of administration was limited, the control of attacks uncertain as well as the evolution of the co-morbid psycho-pathology. Considering the reviews and meta-analysis of complex prophylactic procedures, it must be concluded that their effect is mostly linked to a placebo and non-specific psychological effects. Acupuncture may have a slight specific effect on tension type headache, but not on migraine. Manual therapy studies do not exhibit difference between manipulation, mobilization, and controls; touch has no proven specific effect. A comprehensive efficacy review of biofeedback studies concludes to a small specific effect on tension type headache but not on migraine. A review of behavioral treatment conclude to an interesting mean improvement but did not demonstrated a specific effect with the exception of a four arm study including a pseudo meditation control group. Expectation-linked placebo, conditioning, and non-specific psychological effects vary according clinical situations and psychological context; likely low in RCT, high after anempathic medical contact, and at its maximum with a desired charismatic healer. The announcements of doctors strongly influence the beliefs of patients, and in consequence their pain and anxiety sensibilities; this modulates the amplitude of the placebo and the non-specific psychological effects and is therefore a major determinant of the therapeutic success. Furthermore, any repetitive contact, even through a placebo, may interfere positively with the psychopathological co-morbidity. One has to keep in mind that the non-specific psychological interactions play a major role in the improvement of the majority of the headache sufferers.

Athletes' inclination to play through pain: a coping perspective

Previous studies have shown how social networks lead athletes to accept pain as a "part of the game," which generates pressure on athletes to continue competing despite being in pain. Little is known, however, about the potential coping strategies that are related to pain behavior in sport. This study of 205 combat athletes examined whether pain coping strategies, including distraction from pain, praying, reinterpreting pain sensations, ignoring pain, and pain catastrophizing, are related to athletes' inclination to play through pain. Results revealed that pain catastrophizing led athletes to reduce their physical involvement in their sport activity. Of particular interest was the moderating effect of ignoring pain such that ignoring pain significantly attenuated the negative effect of pain intensity on athletes' inclination to play through pain. Few studies have tested and supported the contribution of pain coping to the prediction of behavior in real sport situations. By identifying which coping strategies athletes could use to maintain their physical involvement despite being in (sometimes intense) pain, the current study makes an important contribution for tailoring pain management programs for this at-risk population.

Sensory disturbances in complex regional pain syndrome: clinical observations, autonomic interactions, and possible mechanisms

OBJECTIVE

To review mechanisms that might contribute to sensory disturbances and sympathetically-maintained pain in complex regional pain syndrome (CRPS).

BACKGROUND

CRPS is associated with a range of sensory and autonomic abnormalities. In a subpopulation of patients, sympathetic nervous system arousal and intradermal injection of adrenergic agonists intensify pain.

RESULTS

Mechanisms responsible for sensory abnormalities in CRPS include sensitization of primary afferent nociceptors and spinothalamic tract neurons, disinhibition of central nociceptive neurons, and reorganization of thalamo-cortical somatosensory maps. Proposed mechanisms of sympathetically-maintained pain include adrenergic excitation of sensitized nociceptors in the CRPS-affected limb, and interaction between processes within the central nervous system that modulate nociception and emotional responses. Central mechanisms could involve adrenergic facilitation of nociceptive transmission in the dorsal horn or thalamus, and/or depletion of bulbo-spinal opioids or tolerance to their effects.

CONCLUSIONS

Sympathetic neural activity might contribute to pain and sensory disturbances in CRPS by feeding into nociceptive circuits at the site of injury or elsewhere in the CRPS-affected limb, within the dorsal horn, or via thalamo-cortical projections.

Stress and tension-type headache mechanisms

Stress is widely demonstrated as a contributing factor in tension-type headache (TTH). The mechanisms underlying this remain unclear at present. Recent research indicates the importance of central pain processes in tension-type headache (TTH) pathophysiology. Concurrently, research with animals and healthy humans has begun to elucidate the relationship between stress and pain processing in the central nervous system, including central pain processes putatively dysfunctional in TTH. Combined, these two fields of research present new insights and hypotheses into possible mechanisms by which stress may contribute to TTH. To date, however, there has been no comprehensive review of this literature. The present paper provides such a review, which may be valuable in facilitating a broader understanding of the central mechanisms by which stress may contribute to TTH.

Attentional and emotional mechanisms of pain processing and their related factors: a structural equations approach

BACKGROUND/OBJECTIVE

It is known that maladaptive attentional and emotional mechanisms of pain processing - as indicated by constructs such as pain hypervigilance, pain-related anxiety and pain catastrophizing - play an important role in the development and maintenance of chronic pain conditions. However, little is known to date about the potential risk factors for these forms of maladaptive processing. The aim of the present study was to shed more light on this issue. A very comprehensive set of predictor variables was examined in healthy pain-free subjects.

METHOD

Participants were 92 young and healthy subjects (mean [+/- SD] age 26.99+/-6.90 years; 47 men, 45 women). Maladaptive attentional and emotional mechanisms of pain processing were assessed by self-report measures of pain hypervigilance, pain-related anxiety and pain catastrophizing, as well as by a dot-probe task. The comprehensive set of predictor variables included measures of affective and bodily distress (depression, anxiety and somatization), experimental pain sensitivity, and cortisol reactivity. Directed relationships were estimated by using structural equation modelling.

RESULTS

Structural equation modelling revealed a significant path from affective and bodily distress to self-reported maladaptive attentional and emotional pain processing. In contrast, the paths from pain sensitivity and cortisol reactivity did not reach the level of significance.

CONCLUSION

These results support the position that anxiety and depression, as well as somatization, contribute to the aberrance of attentional and emotional mechanisms of pain processing. Surprisingly, the assumption of a close relationship between these maladaptive mechanisms of pain processing and pain sensitivity could not be confirmed.

The silent healer: the role of communication in placebo effects

Placebo effects have an ambiguous reputation, as they are associated with sham treatment and deceit on the one hand and as interesting phenomena, which might be clinically relevant on the other. The goal of this paper is to demonstrate that placebo effects are relevant and can be used as an effective part of many treatments by using communication targeting placebo effect mechanisms. We examined the history of placebos and the placebo effect, addressing common misconceptions and disentangling ambiguities. We then reviewed whether the placebo effect can be robustly shown in the current literature, and zoomed in on the plausible mechanisms (conditioning, expectancies and affect manipulation) through which the placebo effect might be produced. Observing the link with the doctor-patient communication literature, and pleading for a better integration of the two research traditions we conclude by setting out a research agenda for testing the role of communication in placebo effects.