Prevalence of post-traumatic stress disorder in fibromyalgia patients: overlapping syndromes or post-traumatic fibromyalgia syndrome?

Fibromyalgia: present to future

There has been a dramatic increase in our understanding of fibromyalgia throughout the past 14 years since the publication of the 1990 American College of Rheumatology classification criteria. Before 1990, and for most of the 20th century, fibromyalgia was considered to be predominantly a muscle disorder; now the critical abnormality is described as "central sensitization." However, central sensitization has to have an initial genesis and nociceptive stimuli from painful foci in muscle are increasingly recognized as being relevant to the development of fibromyalgia. Clinicians also recognize an association between the initiation of fibromyalgia and chronic psychologic stressors and inflammatory disorders. It has been more difficult to understand how two such apparently diverse events could affect central pain physiology. However, some clues are emerging from the role of diverse stimuli in activating glial cells and the role of disordered cytokine networks. Some predictions about future developments in fibromyalgia are ventured based on the current state of knowledge.

Genetics of fibromyalgia

The pathogenesis of fibromyalgia (FM) and related conditions is not entirely understood. Recent evidence suggests that these syndromes may share heritable pathophysiologic features. Familial studies suggest that genetic and familial factors may play a role in the etiopathogenesis of these conditions. There is evidence that polymorphisms of genes in the serotoninergic and catecholaminergic systems are linked to the pathophysiology of FM and related conditions and are associated with personality traits. The precise role of genetic factors in the etiopathology of FM remains unknown, but it is likely that several genes are operating together to initiate this syndrome. Larger longitudinal studies are needed to better clarify the role of genetics in the development of FM.

A new view on hypocortisolism

Low cortisol levels have been observed in patients with different stress-related disorders such as chronic fatigue syndrome, fibromyalgia, and post-traumatic stress disorder. Data suggest that these disorders are characterized by a symptom triad of enhanced stress sensitivity, pain, and fatigue. This overview will present data on the development, mechanisms and consequences of hypocortisolism on different bodily systems. We propose that the phenomenon of hypocortisolism may occur after a prolonged period of hyperactivity of the hypothalamic-pituitary-adrenal axis due to chronic stress as illustrated in an animal model. Further evidence suggests that despite symptoms such as pain, fatigue and high stress sensitivity, hypocortisolism may also have beneficial effects on the organism. This assumption will be underlined by some studies suggesting protective effects of hypocortisolism for the individual.

Estrogen regulates adrenal medullary function producing sexual dimorphism in nociceptive threshold and beta-adrenergic receptor-mediated hyperalgesia in the rat

Epinephrine produces sexually dimorphic beta(2)-adrenergic receptor-mediated mechanical hyperalgesia, with male rats exhibiting greater hyperalgesia. Because female rats have higher plasma epinephrine levels, and beta-adrenergic receptor sensitivity is affected by chronic exposure to agonists, we tested the hypothesis that this sexual dimorphism is due to epinephrine-induced desensitization of beta(2)-adrenergic receptors. Following gonadectomy, epinephrine hyperalgesia, as measured by the Randall-Selitto paw-withdrawal test, was unchanged in male rats while in females it was increased. Prepubertal male and female rats do not demonstrate sexual dimorphism in either plasma epinephrine level or epinephrine-induced hyperalgesia. Adrenal medullectomy and adrenal denervation both significantly enhanced epinephrine hyperalgesia, but only in females. In contrast, the sexually dimorphic hyperalgesia induced by prostaglandin E(2), another agent that acts directly to sensitize primary afferent nociceptors, was not enhanced by adrenal medullectomy or denervation. Chronic administration of epinephrine in male rats, to produce plasma levels similar to those of gonad-intact females, significantly attenuated epinephrine-induced hyperalgesia, making it similar to that in females. These results strongly support the suggestion that estrogen regulates plasma epinephrine in female rats and differential sensitivity to beta(2)-adrenergic agonists accounts for the sexual dimorphism in epinephrine-induced hyperalgesia. Unexpectedly, regulation of adrenal medullary function by estrogen was also found to modulate baseline nociceptive threshold such that females had a lower nociceptive threshold.

Sexual and Physical Abuse in Women With Fibromyalgia Syndrome

OBJECTIVES

According to the trauma hypothesis, women with fibromyalgia syndrome (FMS) are more likely to report a history of sexual and/or physical abuse than women without FMS. In this study, we rely on a community sample to test this hypothesis and the related prediction that women with FMS are more likely to have posttraumatic stress disorder than women without FMS.

METHODS

Eligibility for the present study was limited to an existing community sample in which FMS and major depressive disorder were prevalent. The unique composition of the original sample allowed us to recruit women with and without FMS from the community. A total of 52 female participants were enrolled in the present FMS group and 53 in the control (no FMS) group. Sexual and physical abuse were assessed retrospectively using a standardized telephone interview.

RESULTS

Except for rape, sexual and physical abuse were reported equally often by women in the FMS and control groups. Women who reported rape were 3.1 times more likely to have FMS than women who did not report rape (P<0.05). There was no evidence of increased childhood abuse in the FMS group. Women with FMS were more likely to have posttraumatic stress disorder symptoms (intrusive thoughts and arousal) as well as posttraumatic stress disorder diagnosis (P<0.01).

DISCUSSION

With the exception of rape, no self-reported sexual or physical abuse event was associated with FMS in this community sample. In accord with the trauma hypothesis, however, posttraumatic stress disorder was more prevalent in the FMS group. Chronic stress in the form of posttraumatic stress disorder but not major depressive disorder may mediate the relationship between rape and FMS.

The role of life stress in fibromyalgia

This paper focuses on recent evidence of etiopathogenetic links between fibromyalgia and life stress. From an etiologic point of view, studies concerning the role of adverse life events, personality and lifestyle factors, post-traumatic stress, and negative childhood experiences are reviewed. From a pathogenetic point of view, neurobiologic links between stress and fibromyalgia symptoms, notably chronic pain and fatigue are highlighted. Finally, several methodologic issues with regard to stress research on fibromyalgia, as well as the clinical relevance of the stress concept for fibromyalgia are discussed.

The development of persistent pain and psychological morbidity after motor vehicle collision: integrating the potential role of stress response systems into a biopsychosocial model

OBJECTIVES

Persistent pain and psychological sequelae are common after motor vehicle collision (MVC), but their etiology remains poorly understood. Such common sequelae include whiplash-associated disorders (WAD), fibromyalgia, and posttraumatic stress disorder (PTSD). Increasing evidence suggests that these disorders share overlapping epidemiologic and clinical features. A model is proposed in which central neurobiological systems, including physiologic systems and neuroanatomical structures involved in the stress response, are an important substrate for the development of all 3 disorders and interact with psychosocial and other factors to influence chronic symptom development.

METHODS

Epidemiologic and clinical characteristics regarding the development of these disorders after MVC are reviewed. Evidence suggesting a role for stress response systems in the development of these disorders is presented.

RESULTS

Contemporary evidence supports a model of chronic symptom development that incorporates the potential for interactions between past experience, acute stress responses to trauma, post-MVC behavior, and cognitive/psychosocial consequences to alter activity within brain regions which process pain and to result in persistent pain, as well as psychological sequelae, after MVC. Such a model incorporates factors identified in prior biopsychosocial theories and places them in the landscape of our rapidly developing understanding of stress systems and CNS pain-modulating pathways.

CONCLUSION

New models are needed to stimulate deeper examination of the interacting influences of initial tissue damage, acute pain, psychosocial contingencies, and central stress pathways during chronic symptom development after MVC. Deeper understanding could contribute to improved treatment approaches to reduce the immense personal and societal burdens of common trauma-related disorders.

Relationship between post-traumatic stress disorder and pain in two American Indian tribes

OBJECTIVES

To estimate the association of lifetime post-traumatic stress disorder (PTSD) and pain in American Indians, and determine if tribe, sex, cultural and psychosocial factors, or major depression influence the magnitude of this association.

DESIGN

A cross-sectional probability sample survey completed between 1997 and 2000. A structured interview was conducted by trained, tribal members to gather information on demographic and cultural features, physical health status, psychiatric disorders, and functional status.

SETTING

General community.

PARTICIPANTS

A total of 3,084 individuals randomly selected from the tribal rolls of a Southwestern (N = 1,446) and a Northern Plains (N = 1,638) tribal group who were 15-54 years of age and lived on or within 20 miles of their reservations.

OUTCOME MEASURES

Bodily pain subscale of the Short Form-36. Linear regression models were fit to examine the association between lifetime PTSD and pain, adjusting for demographic, cultural, psychosocial features, painful medical conditions, and major depression.

RESULTS

The prevalence of lifetime PTSD was 16% in the Southwestern and 14% in the Northern Plains; women were nearly twice as likely as men to have lifetime PTSD in both tribes. The final adjusted model demonstrated that mean Short Form-36 bodily pain subscale scores were lower (indicating more pain) among individuals with lifetime PTSD than those without lifetime PTSD. Effect modification by tribe, sex, and depression was not observed.

CONCLUSIONS

Lifetime PTSD was strongly associated with bodily pain in this rural sample of American Indians. Clinicians should be aware of, and address, the link between physical pain syndromes and PTSD.

Prevalence of post-traumatic stress disorder symptoms in orofacial pain patients

OBJECTIVE

There is a high comorbidity between symptoms of post-traumatic stress disorder (PTSD) and chronic pain incidence. The objective of this investigation was to determine the prevalence of PTSD symptoms in chronic orofacial pain patients.

STUDY DESIGN

The study included 1478 adult patients (mean age 36.4 +/- 12.7 years) with primary diagnoses of masticatory/cervical muscle pain or temporomandibular joint pain. Patients completed a battery of psychometric questionnaires including a screening for PTSD symptoms. The sample was divided into a PTSD-positive group (n=218, 15%) a PTSD-negative group (n=551, 37%), and a no-stressor group (n=709, 48%) according to stressor incidence and symptom severity.

RESULTS

The current prevalence of PTSD symptomatology was considerably higher than that reported in surveys from the general population. Patients in the PTSD-positive symptom group reported significantly higher psychological distress, sleep dysfunction, and pain severity compared to patients in the other groups. Psychological distress as measured by the SCL-90-R reached clinically significant levels only in those patients with PTSD symptomatology.

CONCLUSIONS

The results of this study performed at a tertiary care center suggest that TMD patients without PTSD symptomatology show low levels of psychological distress, if any. Clinically significant levels of psychological distress are likely indicators for PTSD. PTSD screening should be included as part of a routine psychometric test battery in TMD patients.

Genetic factors in neuromuscular pain

Recent evidence suggests that fibromyalgia, a chronic widespread pain condition and related syndromes (chronic fatigue syndrome, irritable bowel syndrome, etc.) may share heritable pathophysiologic features. We review the recent literature on genetic and familial factors found to participate in the pathogenesis of these syndromes, specifically fibromyalgia, including evidence suggesting that serotonin- and dopamine-related genes may play a role in the pathogenesis of these illnesses. The importance of environmental factors triggering these conditions in predisposed individuals is also discussed.

α1-Antitrypsin and fibromyalgia: new data in favour of the inflammatory hypothesis of fibromyalgia

alpha1-Antitrypsin (AAT) circulates in high serum concentrations, and impregnates most body tissues. AAT has a broad anti-inflammatory spectrum, and modulates most inflammatory reactions occurring in human body. Recently, a possible relationship between AAT deficiency (AAT-D) and fibromyalgia (FM) has been raised, with the finding that intravenous infusions of purified human AAT efficiently controlled FM symptoms in two patients with severe hereditary AAT-D. On the other hand, functional magnetic resonance imaging has detected a significant greater activity in pain sensitive areas of the brain in patients with FM, in response to cutaneous stimuli, providing further evidence for a physiological explanation for FM pain. In recent studies abnormal profiles of inflammation markers in serum and biopsies have been found in FM patients. Since most of these inflammation mediators can be inhibited by AAT, these observations would suggest that at least a subset of the FM syndrome could be related to an inflammatory process, possibly due to an imbalance between inflammatory and anti-inflammatory substances, in the soft body tissues. Future directions of research would be: (1) to develop epidemiological studies to determine the gene frequency of AAT deficiency alleles in FM patients; (2) implementation of a double-blind placebo-controlled clinical trial to determine the specific role of AAT augmentation therapy in AAT-D patients with FM; (3) identification of specific laboratory markers for diagnostic and clinical evaluation purposes in FM; (4) application of the newest medical imaging techniques for diagnosis; and (5) identification of genetic, familial, and environmental risk factors suspected to participate in the FM syndrome development.

Fibromyalgia: Present to future

There has been a dramatic increase in our understanding of fibromyalgia throughout the past 14 years since the publication of the 1990 American College of Rheumatology classification criteria. Before 1990, and for most of the 20th century, fibromyalgia was considered to be predominantly a muscle disorder; now the critical abnormality is described as "central sensitization." However, central sensitization has to have an initial genesis and nociceptive stimuli from painful foci in muscle are increasingly recognized as being relevant to the development of fibromyalgia. Clinicians also recognize an association between the initiation of fibromyalgia and chronic psychologic stressors and inflammatory disorders. It has been more difficult to understand how two such apparently diverse events could affect central pain physiology. However, some clues are emerging from the role of diverse stimuli in activating glial cells and the role of disordered cytokine networks. Some predictions about future developments in fibromyalgia are ventured based on the current state of knowledge.

Familial aggregation of depression in fibromyalgia: a community-based test of alternate hypotheses

Numerous studies report that fibromyalgia (FM), a syndrome characterized by widespread pain and generalized tender points, is comorbid with major depressive disorder (MDD). The current study tests two alternate explanations for their comorbidity using a family study methodology. The first is that FM is a depression spectrum disorder. The second is that depression is a consequence of living with FM. We recruited potential probands by initially screening by telephone for FM and MDD among women in the NY/NJ metropolitan area, randomly selecting telephone numbers from a list of households with women. Eligible women were invited for second stage physical examinations for FM diagnosis and psychiatric interviews for MDD diagnosis. All available adult, first-degree relatives received psychiatric interviews. Relatives of probands were divided into four groups on the basis of the probands' FM and MDD diagnoses (FM+/MDD+ (n = 156), FM+/MDD- (n = 51), FM-/MDD+ (n = 351) and FM-/MDD- (n = 101)). Results indicated that rates of MDD in the relatives of probands with FM but without personal histories of MDD were virtually identical to rates of MDD in relatives of probands with MDD themselves. This outcome is consistent with the hypothesis that FM is a depression spectrum disorder, in which FM and MDD are characterized by shared, familially mediated risk factors. The implications of these findings for a stress-vulnerability model of FM are discussed.

Fibromyalgia pain: do we know the source?

PURPOSE OF REVIEW

Fibromyalgia Syndrome (FMS) is a chronic pain condition of unknown origin. Multiple abnormalities have been described, including peripheral tissue and central nervous system changes. The relation of these mechanisms, however, is likely bidirectional. FMS pain clearly depends on peripheral nociceptive input as well as abnormal central pain processing. This review will focus on the role of peripheral nociceptive input for pain in FMS.

RECENT FINDINGS

There is strong evidence for abnormal central pain processing in FMS. Sensitized spinal cord neurons in the dorsal horn are responsible for augmented pain processing of nociceptive signals from the periphery. In addition, glial activation, possibly by cytokines and excitatory amino acids may play a role in the initiation and perpetuation of this sensitized state.

SUMMARY

Nociceptive input clearly plays an important role in FMS. Acute or repetitive tissue injury has been associated with FMS pain. Cytokines related to such injuries may be responsible for long-term activation of spinal cord glia and dorsal horn neurons, thus resulting in central sensitization. A better understanding of these important neuro-immune interactions may provide relevant insights into future effective therapies.

Comorbidity of Fibromyalgia and Posttraumatic Stress Disorder Symptoms in a Community Sample of Women

OBJECTIVE

To test alternative explanations for the comorbidity between fibromyalgia (FM), a medically unexplained syndrome involving widespread pain, and posttraumatic stress disorder (PTSD). In contrast to a default "risk factor" hypothesis, tested hypotheses were that: A) The association is due to a sampling bias introduced by the study of care-seeking individuals; B) FM is an additive burden that strains coping resources when confronting life stress; and C) Arousal symptoms of PTSD and FM are confounded.

DESIGN

Community-dwelling women in the New York/New Jersey metropolitan area (N=1,312) completed a telephone survey regarding FM-like symptoms prior to September 11, 2001. Approximately 6 months after the World Trade Center terrorist attacks, they again completed the survey, to which questions regarding PTSD symptoms were added.

RESULTS

The odds of probable PTSD were more than three times greater in women with FM-like symptoms, both assessed after 9/11. The odds ratio was not reduced by controlling for FM-like symptoms before 9/11 or for the potentially confounded symptoms of PTSD specifically related to arousal.

CONCLUSIONS

These findings lead us to reject alternate explanations for the comorbidity between FM and PTSD. Speculations that FM and PTSD share psychobiological risk factors remain plausible.

Epidemiology of fibromyalgia

Chronic widespread pain, the cardinal symptom of fibromyalgia (FM), is common in the general population, with comparable prevalence rates of 7.3% to 12.9% across different countries. The prevalence of FM in the general population was reported to range from 0.5% to 5% and up to 15.7% in the clinic. The common association of FM with other rheumatic disorders, chronic viral infections, and systemic illnesses has been well documented in several studies. Up to 65% of patients with systemic lupus erythematosus meet the criteria for FM. FM is considered a member of the family of functional somatic syndromes. These syndromes are very common and share a similar phenomenology, epidemiologic characteristics, high rates of occurrence, a common pathogenesis, and similar management strategies. A high prevalence of FM was demonstrated among relatives of patients with FM and it may be attributed to genetic and environmental factors.

Pharmacological therapies in fibromyalgia

The fibromyalgia syndrome (FMS) is a common, chronic, widespread pain disorder that mainly affects middle-aged women. In addition to pain complaints, fatigue and disturbed sleep are symptoms frequently reported by these patients. Many FMS patients also meet diagnostic criteria for mood disorders (e.g. depression) as well as other so-called 'functional somatic syndromes', including irritable bowel syndrome, temporomandibular joint disorder, and subsets of chronic low-back pain. A wide variety of medications are used to manage the eclectic symptomatology of FMS patients, although relatively few have been rigorously tested. This chapter provides a contemporary update of the state of FMS pharmacotherapy, with an emphasis on compounds that have been tested in double-blind, randomized, controlled trials. Particular attention is paid to the efficacy of these therapies on the associated symptoms and co-morbid syndromes commonly seen in FMS patients.