Pain in patients with fibromyalgia syndrome.

Chronic diffuse pain and hyperalgesia are two cardinal features of pain in fibromyalgia syndrome (FMS). Advancement in understanding the pathophysiology and treatment efficacy often depends on pain that is defined and measured. Pain is a subjective phenomenon that we can measure only by indirect methods. In this article, we provide methodological guidelines for pain assessment and review recent developments in understanding pain mechanisms and evaluating treatments in FMS. Finally, we demonstrate the heterogeneity of the FMS population and suggest the need for matching treatments to patient characteristics in order to improve clinical outcomes.

Prevalence and impact of posttraumatic stress disorder-like symptoms on patients with fibromyalgia syndrome.

OBJECTIVE: Traumatic events can result in a set of symptoms including nightmares, recurrent and intrusive recollections, avoidance of thoughts or activities associated with the traumatic event, and symptoms of increased arousal such as insomnia and hypervigilance. These posttraumatic stress disorder (PTSD)-like symptoms are frequently observed in persons with chronic pain syndromes. Little is known about how these two phenomena interact with one another. The present study evaluated PTSD-like symptoms in patients with fibromyalgia syndrome (FMS) and examined the relation between PTSD-like symptoms and problems associated with FMS. DESIGN: Ninety-three consecutive patients underwent a comprehensive FMS evaluation and completed self-report questionnaires measuring PTSD-like symptoms, disability, and psychosocial responses to their pain condition. Subjects were divided in two groups based on level of self-reported PTSD-like symptoms. RESULTS: Approximately 56% of the sample reported clinically significant levels of PTSD-like symptoms (PTSD+). The PTSD+ patients reported significantly greater levels of pain (p < 0.01), emotional distress (p < 0.01), life interference (p < 0.01), and disability (p < 0.01) than did the patients without clinically significant levels of PTSD-like symptoms (PTSD-). Over 85% of the PTSD+ patients compared with 50% of the PTSD- patients demonstrated significant disability. Based on response to the Multidimensional Pain Inventory, a significantly smaller percentage of PTSD+ patients were classified as adaptive copers (15%) compared with the PTSD- group (48.2%). CONCLUSIONS: Results suggest that PTSD-like symptoms are prevalent in FMS patients and may influence adaptation to this chronic illness. Clinicians should assess the presence of these symptoms, as the failure to attend to them in treatment may impede successful outcomes.

Evaluation of the relationship between depression and fibromyalgia syndrome: why aren't all patients depressed?

OBJECTIVE: To examine the relationship between fibromyalgia syndrome (FM) and depression by determining the set of factors that differentiate FM patients with and without depressive disorders. METHODS: A sample of 69 patients with FM underwent a standardized tender point examination and a semistructured psychological interview and completed a set of self-report inventories. RESULTS: Of the sample, 39 met criteria for depressive disorder and 30 did not. Depressed patients with FM were significantly more likely to live alone, report elevated functional limitations, and display maladaptive thoughts than nondepressed patients. Nondepressed patients were significantly more likely to have received prior physical therapy than depressed patients. Pain severity, numbers of positive tender points, and pain intensity of tender points and control points did not differentiate the depressed and nondepressed patients. Discriminant analysis revealed that living status, the perception of functional limitations, maladaptive thoughts, and physical therapy treatment together identified diagnoses of depressive disorders for 78% of the patients. CONCLUSION: Concurrent depressive disorders are prevalent in FM and may be independent of the cardinal features of FM, namely, pain severity and hypersensitivity to pressure pain, but are related to the cognitive appraisals of the effects of symptoms on daily life and functional activities.

Comparison of generalized and localized hyperalgesia in patients with recurrent headache and fibromyalgia.

OBJECTIVES: Research suggests that dysregulated pain modulation may play an important role in recurrent headaches and fibromyalgia syndrome (FMS). The primary objective of this study was to investigate algesic responses in localized cervical and pericranial regions (ie, headache-specific areas) and distal locations (ie, trochanter and gluteal) in patients with primary headaches (tension-type and migraine). The headache patients' algesic responses were compared with those of a sample of patients with musculoskeletal pain who report generalized hyperalgesia, or FMS. METHODS: Seventy patients with mixed headache diagnoses and 66 patients with FMS underwent a standardized examination of generalized hyperalgesia based on American College of Rheumatology criteria. RESULTS: Twenty-eight of the 70 headache patients reported the presence of widespread TP pain, suggesting generalized hyperalgesia. Headache diagnosis was unrelated to the presence or absence of generalized hyperalgesia. The subset of headache patients with generalized hyperalgesia did not differ from the FMS patients in pain sensitivity in the cervical and pericranial areas. Regression analyses revealed that pressure pain sensitivity was significantly related to self-reported pain only in the headache patients with generalized hyperalgesia. CONCLUSIONS: These results suggest that extensive dysregulation in pain modulation is important for a substantial minority of recurrent headache patients, who seem to be quite similar to FMS patients. Differential treatment planning targeting generalized hyperalgesia may be useful in treating headache patients exhibiting generalized hyperalgesia more effectively.

Anger in chronic pain: investigations of anger targets and intensity.

The study was designed to assess the frequency and intensity of patients' anger directed toward various potential targets and how intensity of anger toward different targets was related to the chronic pain experience. Ninety-six chronic pain patients who were referred for a comprehensive evaluation completed questionnaires to assess their levels of anger, pain, distress, and disability. Approximately 70% of the participants reported to have angry feelings. Most commonly, patients reported to be angry with themselves (74%) and health care professionals (62%). The relevance of anger to chronic pain experience seemed to vary across targets. Anger toward oneself was significantly associated with pain and depression, whereas only overall anger was significantly related to perceived disability. The results suggest that anger should be conceptualized as a multifactorial construct. In addition to presence, intensity, and expression of anger, targets of anger may be important to better understand psychological adaptation to chronic pain.

Assessment of patients' reporting of pain: an integrated perspective.

A common assumption about pain is that it always results from the presence of underlying organic pathology. In the absence of objective pathology, an individual's report of pain may be ascribed to psychological causes. There is a wide variation in patient's experience of pain and organic factors alone cannot explain individual differences in patients' reports. Assessment of patients who report pain requires attention to psychosocial, behavioural, and organic factors. We describe a comprehensive approach to the assessment of psychological and behavioural variables that affect patients' reports of pain. We counter the duality of the somatogenic versus psychogenic perspective and suggest a more integrated assessment that encompasses not only the severity of pain and related physical pathology but also the person who is reporting the presence of pain.

Improving the rate of classification of patients with the multidimensional pain inventory (MPI): clarifying the meaning of "significant other".

OBJECTIVE: The Multidimensional Pain Inventory (MPI) has been used widely to assess the psychosocial adaptation in chronic pain patients. The MPI can also be used to classify patients into one of three primary subgroups. However, studies have reported that anywhere from 3% to 30% of patients are unclassifiable, mostly attributable to an excessive number of missing responses to questions. The purpose of this study was to examine the reasons for the large number of missing responses and subsequently to reduce the number of patients who cannot be classified within one of the three primary MPI subgroups. DESIGN: Two versions of the MPI were evaluated on two samples of patients (N = 147; and N = 143) with persistent pain being evaluated by the Workers Compensation Board of British Columbia, Canada. One version used the published MPI instructions and the second modified the instructions to clarify the meaning of the term "significant other." In addition, patients were required to designate a significant other who would serve as the anchor for all responses related to a significant other. RESULTS: Approximately 18% of patients could not be classified within one of the three primary profiles and were determined to be unanalyzable using the MPI standard classification procedure. Most patients who could not be classified had excessive missing data to those questions asking about support received from "significant other." Almost all of these patients with missing data were unmarried and living alone. Modifying the instructions of the MPI to specify the meaning of the term "significant other" resulted in an almost threefold (6.3% vs. 18%) reduction in the percentage of patients whose responses could not be analyzed and consequently classified into one of the three primary MPI subgroups. The revised instructions did not lead to any difference in the actual distribution of patients assigned to one of the three profiles. Thus, using the modified instruction did not alter the proportion of patients assigned to one of the three primary groups. CONCLUSION: Modification of the MPI instructions clarifying the definition of a significant other can greatly reduce the number of patients who are classifiable within one of the three primary MPI profiles. Thus, the modified instructions of the MPI (hence the MPI-M) have a significant advantage over the original version. The mean scores on the individual scales of the MPI and the MPI-M are comparable. Moreover, the results demonstrate that the proportion of the previously unanalyzable patients classified within one of the three primary subgroups is comparable to the original proportion of patients assigned to each of the primary subgroups. Thus, it may not be necessary to reestablish the norm scores based on the modified instructions. Future studies and clinicians who wish to use the MPI for the purpose of classifying patients on the basis of psychosocial and behavioral factors should make use of the MPI-M that incorporates the clarification of the meaning of "significant other."

Differential responses by psychosocial subgroups of fibromyalgia syndrome patients to an interdisciplinary treatment.

OBJECTIVES: To evaluate differential treatment responses among 3 empirically derived, psychosocial subgroups of patients with fibromyalgia syndrome to a standard interdisciplinary treatment program. METHOD: Patients were classified into 1 of 3 psychosocial groups on the basis of their responses to the Multidimensional Pain Inventory. Forty-eight patients completed a 6 one-half-day outpatient treatment program consisting of medical, physical, occupational, and psychological therapies spaced over a period of 4 weeks (3 sessions the first week followed by 1 session per week for the next 3 consecutive weeks). RESULTS: Statistically significant reductions were observed in pain, affective distress, perceived disability, and perceived inteference of pain in the patients characterized by poor coping and high level of pain ("dysfunctional" group). In contrast, individuals who were characterized by interpersonal difficulties ("interpersonally distressed" group) exhibited poor responses to the treatment. "Adaptive copers," the third group, revealed significant improvements in pain but due to low pretreatment levels of affective distress and disability showed little improvement on these outcomes. CONCLUSIONS: The results provided support for the hypothesis that customizing treatment based on patients' psychosocial needs will lead to enhanced treatment efficacy. They also emphasize the importance of using appropriate outcome criteria, as low levels of problems at baseline are not likely to show significant changes following any treatment.

Interdisciplinary treatment for fibromyalgia syndrome: clinical and statistical significance.

OBJECTIVES: The primary purposes of the study were to: evaluate the treatment efficacy of an outpatient, interdisciplinary treatment program for fibromyalgia syndrome (FMS); examine whether treatment gains would be sustained for 6 months following the treatment; assess whether improvements were clinically significant; and delineate the factors associated with clinically significant improvement in pain severity. METHODS: Sixty-seven FMS patients completed a 4-week outpatient program consisting of medical, physical, psychologic, and occupational therapies. Six-month followup data were available for 66% of treated patients. RESULTS: Comparisons between pretreatment and posttreatment measures revealed significant improvements in pain severity, life interference, sense of control, affective distress, depression, perceived physical impairment, fatigue, and anxiety; however, there was no improvement in interpersonal relationships or general activities. Clinically significant improvement in pain severity, using the Reliable Change Index, was obtained by 42% of the sample and was predicted by the pretreatment levels of depression, activity, perceived disability, solicitous responses of significant others, and idiopathic onset. Pretreatment level of pain severity was not a significant predictor of the degree of pain improvement. Comparisons among pretreatment, posttreatment, and 6-month followup data revealed that the patients maintained treatment gains in pain, life interference, sense of control, affective distress, and depression. However, the quadratic polynomial analysis revealed that relapse occurred in the subjective rating of fatigue. CONCLUSIONS: The results suggest that, overall, an outpatient interdisciplinary treatment program was effective in reducing many FMS symptoms. Treatment gains tended to be maintained for at least 6 months. However, there were large individual differences in response to treatment. These results suggest that identification of subgroups of FMS patients and their specific clinical characteristics may be useful for maximizing treatment efficacy.

Adaptation to metastatic cancer pain, regional/local cancer pain and non-cancer pain: role of psychological and behavioral factors.

The present study compared the adaptation of cancer pain patients and chronic non-cancer pain patients. Differences between samples of cancer pain patients with and without metastatic disease were also examined. Cancer pain patients reported comparable levels of pain severity to non-cancer chronic pain patients; however, pain due to cancer was associated with higher levels of perceived disability (t(250) = 2.97, P < 0.004) and lower degree of activity (t(286) = 2.45, P < 0.04). The patients with cancer pain, particularly those with metastatic disease, reported significantly higher levels of support and solicitous behaviors from significant others, compared to non-cancer chronic pain patients. The majority of the cancer patients, both with (81%) and without (84%) metastatic disease as well as non-cancer chronic pain patients (85%), could be classified into one of three psychosocial subgroups that had been previously identified with non-cancer chronic pain patients: 'dysfunctional' (high levels of pain, perceived interference, affective distress and low levels of perceived control and activity), 'interpersonally distressed' (high levels of affective distress, negative responses from significant others and low levels of perceived support) and 'adaptive copers' (low levels of interference and affective distress, high levels of perceived control and activity). The distribution of the profiles was significantly different across groups (chi2(4) = 12.79, P < 0.02). However, within each profile. the response patterns were highly comparable across groups. Thus, contrary to the suggestions of some authors, cancer pain and non-cancer chronic pain patients share many features in common. Furthermore, the heterogeneity of psychosocial adaptation to pain within each patient group suggests the importance of psychological assessment in determining the pain management plan.