Pain, disability and coping reflected in the diurnal cortisol variability in patients scheduled for lumbar disc surgery

When thinking about pain contributes to suffering: the example of pain catastrophizing

ABSTRACT

The extensive literature on the potent role negative thoughts about pain have on the experience of pain and pain-related suffering has documented associations with important neurobiological processes involved in amplifying nociceptive signals. We focus this review on pain catastrophizing (pCAT)- appraisals of pain as threatening, overwhelming, and unmanageable- and review the evidence that these thoughts are learned in childhood through experience and observation of others, particularly caretakers and parents. For children who have learned pCAT, repeated exposures to pain over time activate pCAT and likely contribute to further amplification of pain through changes in the neurobiological pain regulatory systems, which overlap with those regulating the stress response. We propose that repeated pain and stress exposures throughout childhood, adolescence, and into adulthood alter the neurobiology of pain via a repetitive positive feedback loop that increases risk for heightened pain sensitivity over time with repeated exposures. At some point, often precipitated by an acute episode of pain and possibly influenced by allostatic load, pCAT contributes to persistence of episodic or acute pain and exacerbates pain-related suffering. This developmental trajectory is not inevitable, as the impact of pCAT on pain and pain-related suffering can be influenced by various factors. We also present future directions for work in this area.

Pain neuroscience education improves post-traumatic stress disorder, disability, and pain self-efficacy in veterans and service members with chronic low back pain: Preliminary results from a randomized controlled trial with 12-month follow-up

Post-traumatic stress disorder (PTSD) and chronic low back pain (CLBP) are frequently co-morbid. Some research suggests that PTSD and CLBP may share common neurobiological mechanisms related to stress. Traditional biomedical education may be ineffective for PTSD and CLBP, especially when co-morbid. The purpose of this study is to determine if pain neuroscience education (PNE) is more effective than traditional education in reducing PTSD, disability, pain, and maladaptive beliefs in patients with CLBP. Participants with CLBP and possible PTSD/PTSD-symptoms were recruited for this study. Participants were randomly allocated to a PNE group or a traditional education group. The intervention included 30 minutes of education followed by a standardized exercise program once a week for 4-weeks with a 4 and 8-week follow-up and healthcare utilization assessed at 12-months. Forty-eight participants consented for this research study with 39 allocated to treatment (PNE n = 18, traditional n = 21). PNE participants were more likely to achieve a clinically meaningful reduction in PTSD symptoms and disability at short-term follow-up. At 12-months, the PNE group utilized healthcare with 76% lower costs. In participants with CLBP, PNE may reduce hypervigilance toward pain and improve PTSD symptoms. Participants who received PNE were more confident body-tissues were safe to exercise. These beliefs about pain could contribute to a decrease in perceived disability and healthcare consumption for CLBP.

Examining Reactivity and Recovery Patterns of Pain-Evoked Cortisol and Alpha-Amylase Trajectories: Relations Between Psychological Markers of Risk and Resilience

Chronic low back pain (cLBP) is one of the leading causes of disability globally and represents an enormous burden to aging adults. While numerous factors contribute to cLBP, dysregulation in the hypothalamic-pituitary-adrenal axis and autonomic nervous system functioning have been implicated in its pathogenesis. It is well documented that negative psychological states can modulate biological stress responsivity in chronic pain; however, little is known regarding the influence of positive psychological factors in this relationship. The aim of this study was to examine the association between psychological risk and resilience factors with patterns of physiological stress reactivity and recovery in 60 older adults with cLBP. Participants completed measures of hope, optimism, pain catastrophizing, and perceived stress, and underwent psychophysical pain testing assessing responses to painful pressure, heat, and cold stimuli. Salivary samples were obtained prior to pain induction and at 7 time points spanning 90 minutes after pain testing terminated. To examine reactivity and recovery profiles in hypothalamic-pituitary-adrenal axis and autonomic nervous system function, samples were assayed for cortisol and alpha-amylase, respectively. Results revealed higher levels of hope and optimism were associated with increased cortisol reactivity (p's < .003) and more rapid recovery (p's = .001). Further, pain catastrophizing and perceived stress were associated with cortisol reactivity, with lower levels of these factors predicting larger increases in cortisol from baseline to peak levels (p's < .04). No significant differences in reactivity or recovery patterns emerged for alpha-amylase. Overall, findings highlight the role of psychological risk and resilience factors in modulating physiological stress reactivity. PERSPECTIVE: This article investigated whether psychosocial risk and resilience factors were associated with stress reactivity and recovery in response to laboratory-based pain testing in older adults with chronic low back pain. Results indicate that high resilience factors may be protective by modulating adrenocortical reactivity and recovery profiles.

Are biomarkers associated with sensitivity to physical activity?

BACKGROUND

Activity-based treatments play an integral role in managing musculoskeletal conditions including low back pain. However, while therapeutic exercise has been shown to reduce pain in such conditions, certain individuals experience a paradoxical pain increase in response to exercise. The physiological processes underlying this sensitivity to physical activity (SPA) are not fully understood, however stress and inflammation have been shown to contribute to SPA. The present cross-sectional study investigated whether physiological indicators of stress (cortisol) and inflammation (IL-6) help explain SPA.

METHODS

Twenty-seven patients with chronic low back pain and 21 healthy controls completed a 1-h exercise session of standardized physical tasks. SPA was calculated from the difference between post- and pre-exercise pain levels. Participant's saliva was collected at several timepoints for cortisol and IL-6 levels quantification. Their waking cortisol response was calculated to reflect their cortisol regulation. Reactivity of IL-6 and cortisol was calculated to reflect changes in these measures during exercise.

RESULTS

IL-6 reactivity was significantly and positively correlated with SPA among participants with low back pain. In contrast, neither cortisol waking response nor cortisol reactivity was significantly correlated within the low back pain group. No significant differences in IL-6 reactivity, cortisol reactivity or cortisol waking response were observed.

CONCLUSION

These findings are the first to link SPA to an objective biomarker among people with low back pain. These findings help describe the physiological mechanisms of SPA and can support new clinical research that targets the inflammatory response of patients with chronic low-back pain and elevated SPA.

SIGNIFICANCE

This study reveals a correlation between SPA and an objective salivary biomarker of IL-6 in people with low back pain, improving our understanding of this clinically relevant subjective experience.

The waiting game: investigating the neurobiological transition from acute to persistent pain in adolescent rats

Persistent postsurgical pain affects 20% of youth undergoing a surgical procedure, with females exhibiting increased prevalence of chronic pain compared with males. This study sought to examine the sexually-dimorphic neurobiological changes underlying the transition from acute to persistent pain following surgery in adolescence. Male and female Sprague Dawley rats were randomly allocated to a sham or injury (plantar-incision surgery) condition and assessed for pain sensitivity while also undergoing magnetic resonance imaging at both an acute and chronic timepoint within adolescence. We found that injury resulted in persistent pain in both sexes, with females displaying most significant sensitivity. Injury resulted in significant gray matter density increases in brain areas including the cerebellum, caudate putamen/insula, and amygdala and decreases in the hippocampus, hypothalamus, nucleus accumbens, and lateral septal nucleus. Gray matter density changes in the hippocampus and lateral septal nucleus were driven by male rats whereas changes in the amygdala and caudate putamen/insula were driven by female rats. Overall, our results indicate persistent behavioral and neurobiological changes following surgery in adolescence, with sexually-dimorphic and age-specific outcomes, highlighting the importance of studying both sexes and adolescents, rather than extrapolating from male adult literature.

TFOS Lifestyle: Impact of lifestyle challenges on the ocular surface

Many factors in the domains of mental, physical, and social health have been associated with various ocular surface diseases, with most of the focus centered on aspects of dry eye disease (DED). Regarding mental health factors, several cross-sectional studies have noted associations between depression and anxiety, and medications used to treat these disorders, and DED symptoms. Sleep disorders (both involving quality and quantity of sleep) have also been associated with DED symptoms. Under the domain of physical health, several factors have been linked to meibomian gland abnormalities, including obesity and face mask wear. Cross-sectional studies have also linked chronic pain conditions, specifically migraine, chronic pain syndrome and fibromyalgia, to DED, principally focusing on DED symptoms. A systematic review and meta-analysis reviewed available data and concluded that various chronic pain conditions increased the risk of DED (variably defined), with odds ratios ranging from 1.60 to 2.16. However, heterogeneity was noted, highlighting the need for additional studies examining the impact of chronic pain on DED signs and subtype (evaporative versus aqueous deficient). With respect to societal factors, tobacco use has been most closely linked to tear instability, cocaine to decreased corneal sensitivity, and alcohol to tear film disturbances and DED symptoms.

Do catastrophizing and autonomic-reduced flexibility mediate pain outcomes in chronic headache?

OBJECTIVES

Maladaptive cognitive strategies and reduced autonomic flexibility have been reported in chronic pain conditions. No study to date addressed the effects of maladaptive coping and reduced autonomic flexibility, as indexed by heart rate variability (HRV), in chronic headaches. The present study aimed to assess the mediating role of pain catastrophizing and HRV on pain outcomes in patients with chronic headache.

METHODS

Thirty-two chronic headache patients and 28 healthy controls were recruited. Self-reported pain severity, pain interference on daily activity, and pain catastrophizing were assessed through the Multidimensional Pain Inventory and the Pain-Related Self Statements Scale. HRV was recorded at rest. Correlations and mediation analysis between self-report, HRV, and pain outcomes were run.

RESULTS

Patients with chronic headache reported significantly higher pain severity (p < .001; d =  - 1.98), pain interference on daily activity (p < .001; d =  - 1.81), and pain catastrophizing (p < .001; d =  - 0.96) compared to controls. They also presented significantly lower HRV (p < .05; d = 0.57). Both pain catastrophizing and HRV were associated with pain interference on daily activity. However, from mediation analysis, pain catastrophizing only emerged as the mediator for pain severity (p < .001; b = 0.30) and pain interference (p < .001; b = 0.14).

CONCLUSION

Present results showed that chronic headache patients are characterized by high catastrophizing and lower physiological adaptability. Pain catastrophizing emerged as the only mediator of pain outcomes, suggesting that cognitive factors might have a major influence on the severity of pain and its interference on daily activities. Further studies are needed to evaluate these autonomic-cognitive interactions in chronic pain.

Endogenous Modulation of Pain: The Role of Exercise, Stress, and Cognitions in Humans

BACKGROUND

Pain is a complex and highly subjective phenomenon that can be modulated by several factors. On the basis of results from experimental and clinical studies, the existence of endogenous pain modulatory mechanisms that can increase or diminish the experience of pain is now accepted.

METHODS

In this narrative review, the pain modulatory effects of exercise, stress, and cognitions in humans are assessed.

RESULTS

Experimental studies on the effect of exercise have revealed that pain-free participants show a hypoalgesic response after exercise. However, in some patients with chronic pain, this response is reduced or even hyperalgesic in nature. These findings will be discussed from a mechanistic point of view. Stress is another modulator of the pain experience. Although acute stress may induce hypoalgesia, ongoing clinical stress has detrimental effects on pain in many patients with chronic pain conditions, which have implications for the understanding, assessment, and treatment of stress in patients with pain. Finally, cognitive strategies play differing roles in pain inhibition. Two intuitive strategies, thought suppression and focused distraction, will be reviewed as regards experimental, acute, and chronic pain.

CONCLUSION

On the basis of current knowledge on the role of exercise, stress, and cognitive pain control strategies on the modulation of pain, implications for treatment will be discussed.

What Does CATS Have to Do With Cancer? The Cognitive Activation Theory of Stress (CATS) Forms the SURGE Model of Chronic Post-surgical Pain in Women With Breast Cancer

Chronic post-surgical pain (CPSP) represents a highly prevalent and significant clinical problem. Both major and minor surgeries entail risks of developing CPSP, and cancer-related surgery is no exception. As an example, more than 40% of women undergoing breast cancer surgery struggle with CPSP years after surgery. While we do not fully understand the pathophysiology of CPSP, we know it is multifaceted with biological, social, and psychological factors contributing. The aim of this review is to advocate for the role of response outcome expectancies in the development of CPSP following breast cancer surgery. We propose the Cognitive Activation Theory of Stress (CATS) as an applicable theoretical framework detailing the potential role of cortisol regulation, inflammation, and inflammatory-induced sickness behavior in CPSP. Drawing on learning theory and activation theory, CATS offers psychobiological explanations for the relationship between stress and health, where acquired expectancies are crucial in determining the stress response and health outcomes. Based on existing knowledge about risk factors for CPSP, and in line with the CATS position, we propose the SURGEry outcome expectancy (SURGE) model of CPSP. According to SURGE, expectancies impact stress physiology, inflammation, and fear-based learning influencing the development and persistence of CPSP. SURGE further proposes that generalized response outcome expectancies drive adaptive or maladaptive stress responses in the time around surgery, where coping dampens the stress response, while helplessness and hopelessness sustains it. A sustained stress response may contribute to central sensitization, alterations in functional brain networks and excessive fear-based learning. This sets the stage for a prolonged state of inflammatory-induced sickness behavior - potentially driving and maintaining CPSP. Finally, as psychological factors are modifiable, robust and potent predictors of CPSP, we suggest hypnosis as an effective intervention strategy targeting response outcome expectancies. We here argue that presurgical clinical hypnosis has the potential of preventing CPSP in women with breast cancer.

Dysfunctional Coping Mechanisms Contribute to Dry Eye Symptoms

Dysfunctional coping behaviors, such as catastrophizing, have been implicated in pain severity and chronicity across several pain disorders. However, the impact of dysfunctional coping has not been examined under the context of dry eye (DE). This study evaluates relationships between catastrophizing and measures of DE, including pain severity and pain-related daily interference. The population consisted of patients seen at Miami Veterans Affairs eye clinic between April 2016 and October 2017. Patients filled out standardized questionnaires assessing symptoms of DE and eye pain, non-ocular pain, mental health, coping behaviors (Pain Catastrophizing Scale, PCS), and pain-related daily interference as a perceived impact on quality of life (Multidimensional Pain Inventory, Interference Subscale, MPI-Interference), and all patients underwent an ocular surface examination. In total, 194 patients participated, with a mean age of 58.8 ± 9.6 years, the majority being male, non-Hispanic, and black. PCS (catastrophizing) was correlated with DE symptom severity, including Dry-Eye Questionnaire 5 (DEQ5; r = 0.41, p < 0.0005), Ocular Surface Disease Index (OSDI; r = 0.40, p < 0.0005), and neuropathic-like eye pain (Neuropathic Pain Symptom Inventory-Eye (NPSI-Eye; r = 0.48, p < 0.0005). Most tear metrics, on the other hand, did not correlate with PCS. Linear regressions showed that PCS, non-ocular pain intensity, and number of pain conditions were significant predictors of DEQ5 (overall DE symptoms), while PCS and non-ocular pain intensity were predictors of NPSI-Eye scores, as were insomnia scores and analgesic use. In a separate analysis, PCS and DE symptoms (OSDI) associated with pain-related interference (MPI-Interference) along with non-ocular pain intensity, post-traumatic stress disorder (PTSD), number of pain conditions, and non-Hispanic ethnicity. These findings suggest that catastrophizing is not significantly related to signs of DE, but is strongly associated to pain-related symptoms of DE and daily interference due to pain.

Psychosocial Stress Reactivity as Predictor of Operative Outcome in Lumbar Disc Surgery

BACKGROUND

A large proportion of the population suffers from chronic back pain. For optimal treatment, the question arises which patients would benefit from conservative therapy and for whom lumbar disc surgery is most appropriate. It seems reasonable to analyze the impact of paraclinical parameters on the operation outcome to identify patients who would benefit less from surgery or need special pre-/postoperative medical care.

MATERIALS AND METHODS

From March 2012 to July 2014, 32 patients were treated via microscopically supported interlaminar fenestration and discectomy at the Department of Neurosurgery, University Hospital Carl Gustav Carus Dresden. One day before the operation, a cortisol survey was made during the stress response of the Trier Social Stress Test. At the same time, a survey of relevant questionnaires was conducted by which the postoperative symptom experience was made operational and comparable with the evaluation of the same information thirty days afterwards.

RESULTS

It could be shown that there is a connection between cortisol reactivity and the pain burden following operations. Patients with a greater cortisol reaction under stress exposition partially experienced more intense postoperative pain than the patients with a lower cortisol reaction. However, this relationship could only be explained by single significant results, whereas further calculations could not produce any significance.

CONCLUSIONS

Cortisol reactivity seems to be associated with pain development. The inconsistent findings in empiricism as well as in this investigation are indicative of a complex association of postoperative pain and cortisol reactivity, which needs to be examined further.

Catastrophizing, pain, and functional outcomes for children with chronic pain: a meta-analytic review

Pediatric chronic pain is associated with numerous negative outcomes including increased physical disability, increased rates of depression and anxiety, and decreased quality of life (QOL). Pain catastrophizing-broadly conceptualized as including rumination, magnification, and helplessness cognitions surrounding one's pain-has been linked with poor functional outcomes in children with chronic pain. Pain catastrophizing in pediatric chronic pain is often considered a key factor on which to focus treatment efforts. However, absent a systematic review that integrates the relevant literature, this call for routine assessment and targeted treatment may be premature. This study aimed to: (1) meta-analytically quantify the relationship between catastrophizing and pain and functional/psychosocial outcomes (functional disability/physical functioning, anxiety, depression, and QOL) in children with chronic pain, and (2) examine potential moderators of these relationships. Using a random-effects model, a total of 111 effect sizes from 38 studies were analyzed. Effect sizes ranged from medium to large, with anxiety, depression, and QOL demonstrating a strong association with catastrophizing. Pain intensity and physical disability had a moderate association with catastrophizing. These relationships were robust, minimizing potential publication bias. None of the examined moderators were significant. The strong relationships found between catastrophizing and anxiety, depression, and QOL suggest that successfully intervening on catastrophizing could have far reaching implications in improving pain outcomes in pediatric chronic pain.

Psychobiological Factors Affecting Cortisol Variability in Human-Dog Dyads

Stress responses within dyads are modulated by interactions such as mutual emotional support and conflict. We investigated dyadic psychobiological factors influencing intra-individual cortisol variability in response to different challenging situations by testing 132 owners and their dogs in a laboratory setting. Salivary cortisol was measured and questionnaires were used to assess owner and dog personality as well as owners' social attitudes towards the dog and towards other humans. We calculated the individual coefficient of variance of cortisol (iCV = sd/mean*100) over the different test situations as a parameter representing individual variability of cortisol concentration. We hypothesized that high cortisol variability indicates efficient and adaptive coping and a balanced individual and dyadic social performance. Female owners of male dogs had lower iCV than all other owner gender-dog sex combinations (F = 14.194, p<0.001), whereas owner Agreeableness (NEO-FFI) scaled positively with owner iCV (F = 4.981, p = 0.028). Dogs of owners high in Neuroticism (NEO-FFI) and of owners who were insecure-ambivalently attached to their dogs (FERT), had low iCV (F = 4.290, p = 0.041 and F = 5.948, p = 0.016), as had dogs of owners with human-directed separation anxiety (RSQ) or dogs of owners with a strong desire of independence (RSQ) (F = 7.661, p = 0.007 and F = 9.192, p = 0.003). We suggest that both owner and dog social characteristics influence dyadic cortisol variability, with the human partner being more influential than the dog. Our results support systemic approaches (i.e. considering the social context) in science and in counselling.

Cortisol, Health, and Coping in Patients with Nonspecific Low Back Pain

Subjective health complaints (SHC), including nonspecific low back pain (LBP) as the most common single complaint, are the main reasons for long-term sick leave in many western countries. These complaints are often attributed to "stress". Cortisol has frequently been considered a biomarker reflecting sustained physiological HPA-axis activity, and is characterized by a high cortisol awakening response (CAR) and low evening values. The aim of the study was to investigate whether LBP patients had a normal characteristic cortisol profile, and whether possible deviations were related to coping and health. 305 patients on long-term sick leave for LBP participated in the study, and saliva cortisol profiles were compared to a reference population consisting of Danish workers. Cortisol was measured upon awakening, after 30 min, and in the evening. Additionally, patients answered questionnaires about SHC, fatigue, pain, coping, and social support. The patients showed a seemingly normal cortisol profile. However, CAR was larger among patients compared to the reference population. Patients with low cortisol reactivity had more SHC, pain, and fatigue, and those with higher evening cortisol reported higher scores on coping. The results are discussed in terms of theory, practical considerations, and possible mechanisms for the association between cortisol, health, and coping.

The role of physical status versus mental status in predicting the quality of life of patients with lumbar disk herniation

PURPOSE

To explore the role of physical status versus mental status in predicting the quality of life (QOL) of patients with lumbar disk herniation (LDH).

METHOD

In this correlative study 51 patients with LDH were recruited in their conservative stage of treatment. After profiling their physical status, all participants reported about pain level (according to VAS), pain perception using the Pain Catastrophizing Scale (PCS), and disability level (according to Oswestry Low Back Pain Disability Questionnaire). Their mental status was evaluated using the Spielberger's State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI-II). Their QOL was evaluated by the World Health Organization Quality of Life Questionnaire, brief version (WHOQOL-BREF).

RESULTS

Physical status/disability level correlated with anxiety and depression. While Physical status predicted physical QOL, mental status, and mainly anxiety and depression were the significant predictors of psychological, social, and environmental QOL.

CONCLUSIONS

Mental status may play a significant role in reducing most QOL domains among patients with LDH. The evaluation and intervention process should consider both physical and mental status and their relation to the person's QOL. Since QOL is a major parameter in determining intervention type and success this elaborated perspective may contribute to the intervention planning and outcomes. Implications for rehabilitaion A significant mental distress may accompany the physical disability of patients with LDH. The role of this mental distress in reducing the QOL of patients with LDH may be greater than that of their physical disability. The evaluation and intervention for patients with LDH should refer to both physical and mental status and explore their impacts on quality of life in order to elevate intervention success.

Chronic stress, cortisol dysfunction, and pain: a psychoneuroendocrine rationale for stress management in pain rehabilitation

Pain is a primary symptom driving patients to seek physical therapy, and its attenuation commonly defines a successful outcome. A large body of evidence is dedicated to elucidating the relationship between chronic stress and pain; however, stress is rarely addressed in pain rehabilitation. A physiologic stress response may be evoked by fear or perceived threat to safety, status, or well-being and elicits the secretion of sympathetic catecholamines (epinephrine and norepinepherine) and neuroendocrine hormones (cortisol) to promote survival and motivate success. Cortisol is a potent anti-inflammatory that functions to mobilize glucose reserves for energy and modulate inflammation. Cortisol also may facilitate the consolidation of fear-based memories for future survival and avoidance of danger. Although short-term stress may be adaptive, maladaptive responses (eg, magnification, rumination, helplessness) to pain or non-pain-related stressors may intensify cortisol secretion and condition a sensitized physiologic stress response that is readily recruited. Ultimately, a prolonged or exaggerated stress response may perpetuate cortisol dysfunction, widespread inflammation, and pain. Stress may be unavoidable in life, and challenges are inherent to success; however, humans have the capability to modify what they perceive as stressful and how they respond to it. Exaggerated psychological responses (eg, catastrophizing) following maladaptive cognitive appraisals of potential stressors as threatening may exacerbate cortisol secretion and facilitate the consolidation of fear-based memories of pain or non-pain-related stressors; however, coping, cognitive reappraisal, or confrontation of stressors may minimize cortisol secretion and prevent chronic, recurrent pain. Given the parallel mechanisms underlying the physiologic effects of a maladaptive response to pain and non-pain-related stressors, physical therapists should consider screening for non-pain-related stress to facilitate treatment, prevent chronic disability, and improve quality of life.

Salivary cortisol and cold pain sensitivity in female twins

BACKGROUND

There is a dearth of knowledge about the link between cortisol and pain sensitivity.

PURPOSE

We examined the association of salivary cortisol with indices of cold pain sensitivity in 198 female twins and explored the role of familial confounding.

METHODS

Three-day saliva samples were collected for cortisol levels and a cold pressor test was used to collect pain ratings and time to threshold and tolerance. Linear regression modeling with generalized estimating equations examined the overall and within-pair associations.

RESULTS

Lower diurnal variation of cortisol was associated with higher pain ratings at threshold (p = 0.02) and tolerance (p < 0.01). The relationship of diurnal variation with pain ratings at threshold and tolerance was minimally influenced by familial factors (i.e., genetics and common environment).

CONCLUSIONS

Understanding the genetic and non-genetic mechanisms underlying the link between HPA axis dysregulation and pain sensitivity may help to prevent chronic pain development and maintenance.

Circadian rhythm disruption in cancer biology

Circadian rhythms show universally a 24-h oscillation pattern in metabolic, physiological and behavioral functions of almost all species. This pattern is due to a fundamental adaptation to the rotation of Earth around its own axis. Molecular mechanisms of generation of circadian rhythms organize a biochemical network in suprachiasmatic nucleus and peripheral tissues, building cell autonomous clock pacemakers. Rhythmicity is observed in transcriptional expression of a wide range of clock-controlled genes that regulate a variety of normal cell functions, such as cell division and proliferation. Desynchrony of this rhythmicity seems to be implicated in several pathologic conditions, including tumorigenesis and progression of cancer. In 2007, the International Agency for Research on Cancer (IARC) categorized "shiftwork that involves circadian disruption [as] probably carcinogenic to humans" (Group 2A in the IARC classification system of carcinogenic potency of an agentagent) (Painting, Firefighting, and Shiftwork; IARC; 2007). This review discusses the potential relation between disruptions of normal circadian rhythms with genetic driving machinery of cancer. Elucidation of the role of clockwork disruption, such as exposure to light at night and sleep disruption, in cancer biology could be important in developing new targeted anticancer therapies, optimizing individualized chronotherapy and modifying lighting environment in workplaces or homes.

A Mechanism-Based Approach to Prevention of and Therapy for Fibromyalgia

Fibromyalgia syndrome (FMS) is characterized by pain referred to deep tissues. Diagnosis and treatment of FMS are complicated by a variable coexistence with regional pain, fatigue, sleep disruption, difficulty with mentation, and depression. The widespread, deep pain of FMS can be a consequence of chronic psychological stress with autonomic dysregulation. Stress acts centrally to facilitate pain and acts peripherally, via sympathetic vasoconstriction, to establish painful muscular ischemia. FMS pain, with or without a coexistent regional pain condition, is stressful, setting up a vicious circle of reciprocal interaction. Also, stress interacts reciprocally with systems of control over depression, mentation, and sleep, establishing FMS as a multiple-system disorder. Thus, stress and the ischemic pain it generates are fundamental to the multiple disorders of FMS, and a therapeutic procedure that attenuates stress and peripheral vasoconstriction should be highly beneficial for FMS. Physical exercise has been shown to counteract peripheral vasoconstriction and to attenuate stress, depression, and fatigue and improve mentation and sleep quality. Thus, exercise can interrupt the reciprocal interactions between psychological stress and each of the multiple-system disorders of FMS. The large literature supporting these conclusions indicates that exercise should be considered strongly as a first-line approach to FMS therapy.

Experimental pain ratings and reactivity of cortisol and soluble tumor necrosis factor-α receptor II following a trial of hypnosis: results of a randomized controlled pilot study

OBJECTIVE

Current evidence supports the efficacy of hypnosis for reducing the pain associated with experimental stimulation and various acute and chronic conditions; however, the mechanisms explaining how hypnosis exerts its effects remain less clear. The hypothalamic-pituitary-adrenal (HPA) axis and pro-inflammatory cytokines represent potential targets for investigation given their purported roles in the perpetuation of painful conditions; yet, no clinical trials have thus far examined the influence of hypnosis on these mechanisms.

DESIGN

Healthy participants, highly susceptible to the effects of hypnosis, were randomized to either a hypnosis intervention or a no-intervention control. Using a cold pressor task, assessments of pain intensity and pain unpleasantness were collected prior to the intervention (Pre) and following the intervention (Post) along with pain-provoked changes in salivary cortisol and the soluble tumor necrosis factor-α receptor II (sTNFαRII).

RESULTS

Compared with the no-intervention control, data analyses revealed that hypnosis significantly reduced pain intensity and pain unpleasantness. Hypnosis was not significantly associated with suppression of cortisol or sTNFαRII reactivity to acute pain from Pre to Post; however, the effect sizes for these associations were medium-sized.

CONCLUSIONS

Overall, the findings from this randomized controlled pilot study support the importance of a future large-scale study on the effects of hypnosis for modulating pain-related changes of the HPA axis and pro-inflammatory cytokines.

Diurnal cortisol dysregulation, functional disability, and depression in women with ovarian cancer

BACKGROUND

Multiple alterations in circadian rhythms have been observed in cancer patients, including the diurnal rhythm of the adrenal hormone cortisol. Diurnal cortisol alterations have been associated with cancer-related physiological processes as well as psychological stress. Here we investigate alterations in diurnal cortisol rhythm in ovarian cancer patients, and potential links with depression, life stress, and functional disability.

METHODS

Women (n = 177) with suspected ovarian cancer completed questionnaires and collected salivary cortisol 3× daily for 3 consecutive days before surgery. One hundred women were subsequently diagnosed with ovarian cancer and 77 with benign disease. In addition, healthy women (n = 33) not scheduled for surgery collected salivary cortisol at the same time points.

RESULTS

Ovarian cancer patients demonstrated significantly elevated nocturnal cortisol (P = .022) and diminished cortisol variability (P = .023) compared with women with benign disease and with healthy women (all P values <.0001). Among ovarian cancer patients, higher levels of nocturnal cortisol and less cortisol variability were significantly associated with greater functional disability, fatigue, and vegetative depression, but not with stress, distress, or depressed affect. There were no significant associations between functional or psychological variables and diurnal cortisol in women with benign disease.

CONCLUSIONS

Nocturnal cortisol and cortisol variability show significant dysregulation in ovarian cancer patients, and this dysregulation was associated with greater functional disability, fatigue, and vegetative depression. These findings suggest potential hypothalamic-pituitary-adrenal involvement in functional disability in ovarian cancer, and may have implications for disease progression.

Opioid endocrinopathy: a clinical problem in patients with chronic pain and long-term oral opioid treatment

BACKGROUND

The use of strong opioids for treatment of noncancer chronic pain has increased. However, strong evidence for sustained pain relief and improved function is lacking. Controversy prevails, whether hormonal changes are induced by long-term treatment with opioids. The purpose of this study was to investigate the occurrence of endocrine dysfunction in chronic pain patients on long-term opioid treatment.

METHODS

A study group of 39 chronic pain patients treated with strong oral opioids for more than 1 year was compared with a control group of 20 chronic pain patients without opioid treatment. Basic levels of prolactin and function of the hypothalamic-pituitary-thyroid-, hypothalamic-pituitary-adrenal-axis, and hypothalamic-pituitary-growth-hormone - and hypothalamic-pituitary-gonadal-axis were measured. Quality-of-life and side effects were estimated with EORTC-QLQ-C30.

RESULTS

In the opioid-treated group, the patients had signs of pituitary dysfunction affecting all axes. Significant differences were shown in hypofunction of the hypothalamic-pituitary-gonadal -axis, hyperfunction of the hypothalamic-pituitary-adrenal -axis, and higher prolactin levels in the opioid-treated group, compared with the control group. The degree of pain was rated the same in both groups, but the opioid-treated group reported more side effects and lower quality of life.

CONCLUSIONS

Long-term treatment of chronic pain with strong opioids causes side effects that can be attributed to hormonal abnormalities caused by opioid-induced inhibition of hypothalamic-pituitary function. Hormone substitution can be indicated to treat symptoms. Decreasing the opioid dose or stopping the opioid treatment can reverse endocrine dysfunction. This needs to be recognized by all practitioners treating chronic pain patients with opioids.

Changes in situation-specific pain catastrophizing precede changes in pain report during capsaicin pain: a cross-lagged panel analysis among healthy, pain-free participants

Considerable evidence has linked catastrophizing to pain responses, and recent experimental pain research has suggested that situational catastrophizing, measured during or immediately after laboratory pain procedures, is strongly related to pain ratings of standardized noxious stimuli. However, given that most experimental pain protocols involve "static" assessments of pain ratings and catastrophizing at a single time point, the direction by which these factors may affect each other remains unclear. Does catastrophizing influences one's subsequent pain responses or do individual differences in the perceived severity of pain lead to differential rates of catastrophizing? Little is known regarding the course of these variables. Using a cross-lagged panel analysis, we evaluated whether changes in situation-specific catastrophizing preceded changes in laboratory-induced pain responses, or vice versa, during tonic capsaicin pain stimulation. Topical application of a 10% capsaicin cream was applied to the dorsal aspect of the nondominant hand of 38 healthy participants. Situation-specific catastrophizing and pain ratings were obtained at Early (0 to 15 minutes), Mid (15 to 30 minutes), and Final (30 to 35 minutes) periods during capsaicin pain. Analyses revealed that Early-to-Mid changes in catastrophizing ratings prospectively accounted for unique variance in subsequent Mid-to-Final changes in pain ratings, whereas Early-to-Mid changes in pain ratings did not account for unique variance in Mid-to-Final changes in catastrophizing ratings. That is, participants who showed the largest initial increases in catastrophizing reported the greatest subsequent increases in pain. Controlling for the reported change in stress did not affect this pattern of results. These findings provide empirical evidence that a situation-specific catastrophizing process might precede and contribute to subsequent increases in pain experience. Limitations of the present study and possible future research directions are discussed.

PERSPECTIVE

The present study adds to a growing literature on prospective associations between catastrophizing and pain. These results provide initial evidence, in healthy individuals, that changes in catastrophizing may precede changes in pain response.

Disability assessment in temporomandibular disorders and masticatory system rehabilitation

The consequences of a disease or condition such as temporomandibular disorders (TMD) include functional limitation and psychosocial disability. These two concepts refer to the individual's experience of limitations in function associated with the affected part of the body and to disarray in one's life, respectively. Models of disability emphasize the individual's self-report in describing these states and the centrality of these concepts as part of the disease and illness process. However, assessment approaches typically used in medicine and especially in dentistry do not yet routinely include these domains. TMD, as a musculoskeletal pain condition, can clearly lead to both limitation and disability, and the available evidence suggests that dentofacial disorders can also lead to both consequences. The relatively low contribution of disease impairment (measured changes in function through objective tests), however, to the reported limitation or disability in either TMD or dentofacial disorders remains complex and poorly understood. This article reviews the overall model of disablement, the necessary properties of measures to assess disablement, the present state of knowledge about these concepts, and what measures should be considered as part of routine assessment.

Pain catastrophizing and salivary cortisol responses to laboratory pain testing in temporomandibular disorder and healthy participants

Pain catastrophizing is an important variable in the context of acute and chronic pain. The neurophysiological correlates of pain catastrophizing, however, have not been rigorously evaluated. We examined the relationship between trait-pain catastrophizing and morning salivary cortisol levels before and following a 45-minute laboratory pain-testing session in healthy, pain-free (n = 22), and temporomandibular disorder (TMD) participants (n = 39). We also examined whether TMD patients evidenced generalized hyperalgesia and hypercortisolism. Pain catastrophizing was associated with a flattened morning salivary cortisol profile in the context of pain testing, irrespective of pain status. Cortisol profiles did not differ between healthy and TMD participants. TMD was associated with mechanical hyperalgesia only at the masseter. These data are the first to show an association between pain catastrophizing and elevated salivary cortisol profiles in the context of standardized experimental pain testing. These findings in both healthy individuals and those with chronic orofacial pain suggest that aberrant adrenocortical responses to pain may serve as a neurophysiologic pathway by which pain catastrophizing enhances vulnerability for development of chronic pain and maintains and/or exaggerates existing pain and associated morbidity.

PERSPECTIVE

Neurophysiological mechanisms by which pain catastrophizing is related to acute and chronic pain recently have come under empirical study. Understanding of these mechanisms has the unique potential to shed light on key central-nervous-system factors that mediate catastrophizing-pain relations and therapeutic benefits associated with changes in catastrophizing and related cognitive processes.

The Neurobiological Underpinnings of Coping With Pain

The biopsychosocial model treats pain as resulting from a complex interaction of biological, psychological, and social factors. Individual differences in approaches to coping with pain-related symptoms are important determinants of pain-related outcomes, and are often classified under the “psychological” category within the biopsychosocial model. However, engagement in various cognitive, affective, and behavioral pain-coping strategies appears to exert biological effects, which we review here. Pain-coping activities such as catastrophizing, distracting oneself from pain sensations, or reappraisal of pain may exert effects on activity in a variety of pain-processing and pain-modulatory circuits within the brain, as well affect the functioning of neuromuscular, immune, and neuroendocrine systems. The interface between pain-related neurobiology and the use of specific pain-coping techniques represents an important avenue for future pain research.

Pain catastrophizing: a critical review

Pain catastrophizing is conceptualized as a negative cognitive-affective response to anticipated or actual pain and has been associated with a number of important pain-related outcomes. In the present review, we first focus our efforts on the conceptualization of pain catastrophizing, highlighting its conceptual history and potential problem areas. We then focus our discussion on a number of theoretical mechanisms of action: appraisal theory, attention bias/information processing, communal coping, CNS pain processing mechanisms, psychophysiological pathways and neural pathways. We then offer evidence to suggest that pain catastrophizing represents an important process factor in pain treatment. We conclude by offering what we believe represents an integrated heuristic model for use by researchers over the next 5 years; a model we believe will advance the field most expediently.

Mind-body interactions in pain: the neurophysiology of anxious and catastrophic pain-related thoughts

The well-accepted biopsychosocial model proposes that the experience of pain and responses to it result from a complex interaction of biological, psychological, and social factors. However, the separation of these constructs is substantially artificial, and we presume that psychological processes have biological effects, that biological processes affect an individual's psychosocial environment, and so on. Considerable research has demonstrated that pain-coping strategies influence perceived pain intensity and physical functioning, and individual differences in styles of pain coping even shape the persistence of long-term pain complaints in some populations. A good deal of this coping research has focused on catastrophizing, which is a generally maladaptive cognitive and emotional mental set that involves feelings of helplessness when in pain, rumination about pain symptoms, and magnification of pain-related complaints. Collectively, catastrophizing has been consistently associated with heightened experiences of pain across a variety of samples. Although catastrophic thinking regarding pain-related symptoms is often classified under the "psychologic" category within the broader biopsychosocial model, we propose that catastrophizing exerts biologic effects that may account for some of its negative consequences. In general, the cognitive and affective processes captured within the construct of catastrophizing may exert effects on the neuromuscular, cardiovascular, immune, and neuroendocrine systems, and on the activity in the pain neuromatrix within the brain. The interface between pain-related neurobiology and processes such as pain-related catastrophizing represents an important avenue for future pain research.