Efficacy of patient education and duloxetine, alone and in combination, for patients with multisystem functional somatic disorder: Study protocol for the EDULOX trial.

BACKGROUND: Multisystem functional somatic disorder is characterized by specific patterns of persistent physical symptoms with a complex biopsychosocial etiology. The disorder can lead to disability and personal suffering. Current treatment options require specialized settings, therefore patients often wait a long time to receive specific treatment. Patient education is considered important in most treatment programs, but has only been investigated sparsely as a stand-alone treatment. Pharmacological treatment is limited to tricyclic antidepressants in low doses with no antidepressant properties. Duloxetine has been found effective in single organ functional disorders. As a treatment for multisystem functional somatic disorder, duloxetine could reduce symptoms and treat comorbid anxiety and depression. It may furthermore enhance the effect of patient education through a hypothesized effect on cognitive functioning. The purpose of the EDULOX trial is to study psycho-EDUcation and duLOXetine alone and in combination. METHODS: This is a nested study design. The parent trial "EDULOX1" (n = 424) will compare a patient education program with enhanced usual care in an open-labelled, randomized controlled trial. In addition to this, eligible participants will furthermore receive either duloxetine or active placebo in the nested, double-blinded, randomized controlled trial, "EDULOX2" (n = 212). Patient and clinician reported outcomes will be collected through questionnaires. CONCLUSION: The EDULOX trial may establish evidence for treatments applicable for the majority of patients with multisystem functional somatic disorder. If effective, duloxetine would be a more tolerable pharmacological treatment option that can target comorbid depression and anxiety, and potentially boost the effect of patient education. Trial registration number The study is registered at www. CLINICALTRIALS: gov (NCT06232473) and the internal list of research projects at the Region of Central Denmark (Case number 1-16-02-305-23). Approval from the Danish Medical Research Ethics Committees (Case number: 2212291) and the Danish Medicines Agency was obtained under EudraCT Number: 2022-002780-30 and Sponsor's Protocol Code Number: 9515.

Is reduced heart rate variability associated with functional somatic disorders? A cross-sectional population-based study; DanFunD.

OBJECTIVES: It has been hypothesised that functional somatic disorders (FSD) could be initiated by sympathetic predominance in the autonomic nervous system as measured by low heart rate variability (HRV). Earlier studies on the association between HRV and FSD are small case-control studies hampered by selection bias and do not consider the great overlap between the various FSDs. The aim of the present study is to assess any associations between HRV and various FSDs and whether chronic stress confounds such an association. DESIGN: A cross-sectional general population-based study. SETTING: The Danish Study of Functional Somatic Disorders conducted 2013-2015 in 10 municipalities in the western part of Greater Copenhagen, Denmark. PARTICIPANTS: A total of 6891 men and women aged 18-72 years were included in the analyses after exclusion of 602 persons with missing HRV data. Various delimitations of FSD (chronic fatigue, chronic widespread pain, irritable bowel and bodily distress syndrome) were identified by validated questionnaires and diagnostic interviews. HRV parameters in time and frequency domains were calculated from successive beat-to-beat heart rate (HR) data using the 'E-motion' HR monitor device during 7 min of supine rest. Chronic stress was assessed by Cohen's self-perceived stress scale. OUTCOME MEASURES: Logistic regression analyses were used to calculate possible associations between the various delimitations of FSD and HRV adjusting for chronic stress. RESULTS: Persons with FSD had a slightly higher mean HR and lower HRV as measured by time domain parameters, whereas associations with frequency domain parameters were not consistent. Adjusting for chronic stress attenuated associations slightly. CONCLUSION: The study supports a sympathetic predominance in persons with FSD, which could not be entirely explained by chronic stress. However, it is not possible to conclude whether the association is a causal factor to or a consequence of FSD.

Lipid metabolism and functional somatic disorders in the general population. The DanFunD study.

OBJECTIVES: Earlier studies on the association between plasma lipid profiles and functional somatic disorders (FSD) are mainly small case control studies hampered by selection bias and do not consider the great overlap between the various FSDs. The aim of the present study was to investigate the associations between various FSDs and plasma lipid profiles (total cholesterol, HDL cholesterol, non-HDL cholesterol and triglycerides) in a large, unselected population. DESIGN: A cross-sectional general population-based study. SETTING: The Danish Study of Functional Somatic Disorders (DanFunD) conducted in 2011-2015 in 10 municipalities in the western part of greater Copenhagen, Denmark. PARTICIPANTS: A total of 8,608 men and women aged 18-76 years were included in the analyses. Various delimitations of FSD such as chronic fatigue, chronic widespread pain, irritable bowel, and bodily distress syndrome were measured using validated self-administrated questionnaires. Lipid parameters were measured from fasting plasma samples using colorimetric slide methods with Vitros 4600/5600 Ortho Clinical Diagnostics. OUTCOME MEASURES: Logistic regression analyses were used to calculate possible associations between plasma lipids and the various delimitations of FSD. Associations are presented by OR (95% CI) and shown in boxplots. RESULTS: We found a positive association between bodily distress syndrome and triglycerides and non-HDL cholesterol and a negative association with HDL-cholesterol, but no consistent association with total cholesterol. A similar pattern was observed for persons with chronic fatigue, and to some degree for persons with chronic widespread pain, whereas persons with irritable bowel did not show a clear association with the lipid profiles. CONCLUSION: This is the first major study on plasma lipid profiles and FSD indicating an association between some delimitations of FSD and an unfavorable lipid profile. Due to the cross-sectional design, it cannot be determined whether the findings are consequences or determinants of FSD. Further studies-preferable prospective studies-are needed.

Social economic factors and the risk of multiple chemical sensitivity in a Danish population-based cross-sectional study: Danish Study of Functional Disorders (DanFunD).

OBJECTIVES: Multiple chemical sensitivity (MCS) is a rare multisystem and poly-symptomatic disease characterised by a report of various somatic symptoms attributed to inhalation of volatile chemicals in usually harmless doses. The aim was to explore four selected social factors and the risk of MCS in the general Danish population. DESIGN: A cross-sectional general population-based study. SETTING: The Danish Study of Functional Disorders was conducted from 2011 to 2015 which included 9656 participants. PARTICIPANTS: A total of 8800 participants were included in analyses after observations with missing data on exposure and/or outcome were excluded. A total of 164 cases fulfilled the questionnaire criteria for MCS. Of the 164 MCS cases, 101 reported no comorbid functional somatic disorder (FSD) and were included in a subgroup analysis. A total of 63 MCS cases fulfilled the criteria for at least one additional FSD, this subgroup was not included in further analysis. The remaining study population without MCS or any FSD were regarded as controls. OUTCOME MEASURES: We used adjusted logistic regression to calculate OR and 95% CIs of MCS and MCS without FSD comorbidities for each social variable separately including education, employment, cohabitation and subjective social status. RESULTS: We found an increased risk of MCS among the unemployed (OR: 2.95, 95% CI: 1.75 to 4.97), and a twofold increased risk of MCS among individuals with low subjective social status (OR: 2.00, 95% CI: 1.08 to 3.70). At the same time, 4 years or more of vocational training were protective of MCS. No significant associations were observed among MCS cases with no comorbid FSD. CONCLUSION: Lower socioeconomic status was found to be associated with a higher risk of having MCS but not with MCS without FSD comorbidities. Due to the cross-sectional design of the study, we cannot determine whether social status is a determinant or a consequence of MCS.

Normative values of short-term heart rate variability in a cross-sectional study of a Danish population. The DanFunD study.

AIMS: The autonomic nervous system includes parasympathetic and sympathetic components that monitor and regulate most of the bodily functions and play a central role in the physiology and homeostasis of the human body. Heart rate variability is a non-invasive tool for quantification of rhythmic fluctuations in heart rate that reflects the function of the autonomic nervous system. The study aims to describe the heart rate variability distribution in the general population, stratified in sex and age groups, which is currently insufficiently described. METHODS: A cross-sectional population-based study recruited participants in 10 municipalities in the western part of the greater Copenhagen area in Denmark, including 6891 men and women aged 18-72 years (participation rate was 29.5%). Short-term heart rate variability measures were obtained and related to age and gender. RESULTS: Both time and frequency domain measures showed a huge variation in the different sex and age groups. Women had a higher median heart rate than men, and the association with age was U-shaped. Measures indicating a predominance of the parasympathetic component in relation to the sympathetic component were more frequent in women and younger age groups. CONCLUSIONS: Both sex and age influence the heart rate variability in this adult Danish population. Therefore, our age- and sex-related reference values of heart rate variability in the time and frequency domain should be used in further epidemiological and clinical research.

Examine the public health impacts of functional somatic disorders using the DanFunD study.

Background: Persistent physical symptoms (e.g. pain, fatigue) are prevalent in the population and some persons may develop a functional somatic disorder (FSD). We still need to explore the limits between general bodily sensations and FSD, and great controversies exist as regard delimitation, occurrence, risk factors, prognosis, and costs of FSD in the general population. This is mainly due to the lack of focused, sufficient powered, population-based epidemiological studies. Material and Methods: The DanFunD study is the largest focused population-based study on FSD and has the potential to answer these crucial questions regarding the FSD disorders. DanFunD has its origin in the Copenhagen area of Denmark and was initiated in 2009 by an interdisciplinary team of researchers including basic scientists, clinical researchers, epidemiologists, and public health researchers. A population-based cohort of nearly 10,000 people have filled in detailed questionnaires, gone through a thorough health examination, and a biobank is established. The cohort was re-examined after five years. Results:The prevalence of FSD in the Danish population is about 10-15% and is twice as common in women as in men. Persons with FSD report impaired daily activities and low self-perceived health, which qualifies FSD as a major public health problem. The research plan to unravel the risk factors for FSD employs a bio-psycho-social approach according to a detailed plan. Preliminary results are presented, and work is in progress. Likewise, plans for assessing prognosis and health care costs are provided. Conclusion: We invite researchers in the field to collaborate on this unique data material.

Physiological Health and Physical Performance in Multiple Chemical Sensitivity-Described in the General Population.

Multiple chemical sensitivity (MCS) is a multifactorial somatic disorder characterized by physical reactions triggered by even extremely low levels of different airborne chemicals. In most individuals with MCS, these reactions have substantial negative impact on social, occupational, and everyday life often including limited or no engagement in physical activities. The aim of this study was to explore associations between MCS and objective measurements of anthropometry, cardiorespiratory health, and physical performance. From the Danish population-based cohort DanFunD counting 9656 participants aged 18-76 years, 1.95% (n = 188) were categorized as MCS individuals (MCS All). Of those 188, 109 participants were subcategorized as having MCS without functional somatic disorders (FSD) (MCS with no comorbid FSD). The remaining study population without any FSD were regarded controls. We used adjusted multiple linear regression analyses to evaluate associations between MCS and anthropometry, cardiorespiratory fitness, and physical performance. Compared with the general population, MCS All had less optimal body composition, increased risk of obesity, impaired cardiorespiratory fitness, and physical performance which was not seen in MCS with no comorbid FSD. MCS individuals may be inhibited to maintain an active lifestyle which can increase risk of obesity and consequently have negatively impact on general health, which may not be the case among MCS with no comorbid FSD.

Are study populations in trials of antidepressants and psychotherapy comparable? A retrospective case study of two parallel running trials for multi- organ functional somatic disorder.

This study retrospectively compares two previous parallel running, randomized, controlled trials of pharmacotherapy (imipramine) and psychotherapy (acceptance and commitment therapy) for multi-organ functional somatic disorder (FSD). Differences in demographics, psychiatric comorbidity, illness severity, and illness duration associated with eligibility for the two trials and patients' willingness to participate are explored using linear or binary regression models. 418 patients with multi-organ FSD was included. We found that 377 (95%) were eligible for psychotherapy and 257 patients (61%) for pharmacotherapy. Patients eligible for pharmacotherapy were less severely impaired, less often received disability pension, reported shorter illness duration and experienced less psychological distress than patients eligible for psychotherapy. Whilst exclusion criteria for both trials differed markedly, it was not possible to clearly identify patient or illness characteristics associated with patients' willingness to participate. The study showed that trial-specific exclusion criteria led to the selection of less complex and less severely impaired patients in the pharmacological trial in this sample of multi-organ FSD. Our findings have important implications for the interpretation and comparability of RCT results of different treatments in multi-organ FSD and may point to some common flaws in study design and interpretation of pharmacological vs. psychotherapeutic intervention trials in psychiatry.

Conditioned pain modulation and pain sensitivity in functional somatic disorders: The DanFunD study.

BACKGROUND: Disrupted pain regulation has been proposed as a component in functional somatic disorders (FSD). The objective of this study was to examine a general population sample, encompassing three delimitations of FSD while assessing pain sensitivity and conditioning pain modulation (CPM). METHODS: Pressure pain thresholds (PPTs) at the tibialis and trapezius muscles were recorded at baseline. During cold pressor stimulation of the hand, the tibialis PPTs were re-assessed and the difference from baseline measures defined the CPM effect. Participants (n = 2,198, 53% females) were randomly selected from the adult Danish population. FSD was established by self-reported symptom questionnaires. RESULTS: With a few exceptions, only weak associations were seen between PPTs and CPM in cases with FSD (p > .1). A high PPT was associated with lower odds of having multi-organ bodily distress syndrome (ORPPT trapezius : 0.66, 95% CI: 0.49-0.88, p = .005), with the symptom profile characterized by all symptoms (ORPPT trapezius : 0.72, 95% CI: 0.58-0.90, p = .003 and ORPPT tibialis : 0.75, 95% CI: 0.62-0.91, p = .004), and with multiple chemical sensitivity (ORPPT trapezius : 0.81, 95% CI: 0.67-0.97, p = .022). High CPM was associated with high odds of having irritable bowel (ORCPM relative : 1.22, 95% CI: 1.04-1.43, p = .013 and ORCPM absolute  = 2.66, 95% CI: 1.07-6.45, p = .033). CONCLUSION: However, only PPT measured over the trapezius muscle were still significant after correction for multiple testing for the symptom profile characterized by all symptoms. Findings from this study do not support altered pain regulation in questionnaire-based FSD which is in contrast with the existing presumption. Further epidemiological studies in this field are needed. SIGNIFICANCE: Disrupted pain regulation as measured by abnormal pain thresholds has been hypothesized as a central mechanism in Functional Somatic Disorders (FSD). The hypothesis has been raised in clinical setting where patients presented subjective and objective features of hypersensitivity. The present population-based study does not support this notion. This points to the importance of further studies into the underlying pathophysiology mechanisms of FSD.

Insulin Resistance Is Associated with Multiple Chemical Sensitivity in a Danish Population-Based Study-DanFunD.

Multiple chemical sensitivity (MCS) is a multisystem syndrome, and limited knowledge of its pathophysiology exists. Based on the population-based Danish cohort DanFunD, this study investigated metabolic health in people with MCS compared to individuals who did not have MCS. From 9656 cohort participants aged 18-76 years old, 1.95% were categorized as MCS individuals with comorbid functional somatic disorders (MCS +FSD, n = 188), and 1.13% were categorized as MCS without functional somatic disorders (MCS ÷FSD, n = 109). MCS was characterized based on three criteria: the experience of symptoms upon exposure to common odors and airborne chemicals, symptoms related the central nervous systems and others organ symptoms, and significant impact on every day, social, and occupational life. The remaining study population without MCS or any other functional somatic disorders were regarded as controls. We used adjusted multiple linear regression with link-function to evaluate the associations between lipid and glucose metabolism markers and MCS. We also tested the odds ratio of metabolic syndrome in MCS. Results did not point to statistically significant associations between lipid biomarkers or metabolic syndrome and both MCS groups compared to the controls. We found that MCS individuals may be more insulin resistant and that MCS ÷ FSD may have an impaired glucose metabolism when compared to controls.

The use of prescription medication in 239 patients with multiple functional somatic syndromes.

OBJECTIVE: To describe the use of prescription drugs and their association with patient characteristics in patients with multiple functional somatic syndromes (FSS) focusing on drugs generally recommended and not recommended in FSS treatment. METHOD: Using data from a national prescription registry, we describe the drug use during a two-year period for 239 trial participants. Using regression models, we analyse the associations of patient characteristics with the patterns of use of antidepressants, anticonvulsants, opioids and sedatives. RESULTS: The use of prescription drugs was highly heterogeneous. Antidepressants were used at least temporarily by 34% (88/239), anticonvulsants by 7% (16/239), opioids by 26% (61/239) and sedatives by 20% (47/239) of the patients. Severe impairment due to multiple FSS was associated with use of opioids or sedatives (OR 6.49 (95% CI 2.68-15.68; p < 0.001)) but also with use of antidepressants or anticonvulsants (OR 3.42 (95% CI 1.35-8.65; p = 0.009)). Poor self-reported physical health, additional physical comorbidities and low socioeconomic status were associated with use of opioids or sedatives only. CONCLUSION: Antidepressants and anticonvulsants were modestly used. Opioids and sedatives were especially used by the severely affected patients. Balancing treatment expectations and enhancing patients' understanding of FSS may direct treatments towards more generally recommended drugs.

Imipramine versus placebo for multiple functional somatic syndromes (STreSS-3): a double-blind, randomised study.

BACKGROUND: Functional somatic syndromes, including chronic fatigue syndrome or irritable bowel syndrome, often co-exist. Treatment guidelines supported by high quality evidence exist for most functional somatic syndromes, but are lacking for multiple comorbid functional somatic syndromes. We aimed to assess the effect of the tricyclic antidepressant, imipramine, in patients with multiple functional somatic syndromes defined by the criteria for multiorgan bodily distress syndrome, a unifying diagnosis that encompasses most functional somatic syndromes and somatoform disorders. METHODS: In this single-centre, double-blind, randomised trial done in a Danish university hospital setting, participants were patients consecutively referred (age 20-50 years) fulfilling criteria for multiorgan bodily distress syndrome with no concurrent comorbid depression or anxiety disorder. Participants were randomly assigned (1:1) to receive either 10 weeks of low-dose imipramine or placebo (oral daily doses of 25-75 mg). The hospital pharmacy handled randomisation (computer-generated) and masking, providing sequentially numbered packs of study drug that were given serially to the participants. All others involved were masked to allocation. Primary outcome was patient-rated overall health improvement on a 5-point clinical global improvement scale. Improvement was defined as patients responding "better" or "much better" as opposed to "unchanged" and "worse" or "much worse" when rating their overall health status after 10 weeks of minimum 25 mg study drug. Analyses included patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01518634. FINDINGS: Between Jan 30, 2012, and Nov 24, 2014, 138 patients were randomly assigned; 70 to receive imipramine and 68 to receive placebo. The study was completed on May 1, 2015. 125 patients received at least one dose of study drug: 65 received imipramine and 60 received placebo. Treatment was terminated prematurely for eight (12%) patients receiving imipramine and seven (12%) patients receiving placebo. Data were missing for two (3%) patients receiving imipramine and three (5%) patients receiving placebo. Of the 120 patients (96%) who provided primary outcome data, 33 (53%) receiving imipramine reported their overall health status as "better" or "much better" compared with 14 patients (25%) receiving placebo. The improvement after imipramine was significantly greater than after placebo (odds ratio 3·3 [95% CI 1·6-6·8]; p=0·001). Number needed to treat was 3·6 (95% CI 2·3-8·9). Analysis of the worst-case scenario for patients with missing outcome did not change the interpretation of the results. 32 patients (49%) receiving imipramine and 10 patients (17%) receiving placebo had at least one adverse event of moderate intensity (p=0·0001); eight patients (12%) receiving imipramine and three patients (5%) receiving placebo had at least one adverse event of severe intensity (p=0·1496). One patient (1%) receiving placebo experienced a serious adverse event (a subdural haematoma sustained after an accident). Adverse events caused dropout in four patients (6%) receiving imipramine and three patients (5%) receiving placebo. INTERPRETATION: Imipramine treatment compared with placebo significantly improved overall health in patients with multiple functional somatic syndromes when both treatments were supported by regular contacts with clinicians. Adverse events were more common in the imipramine group, but only rarely led to discontinuation of treatment. FUNDING: The Danish Foundation, Trygfonden.

A comparison of coping strategies in patients with fibromyalgia, chronic neuropathic pain, and pain-free controls.

Patients suffering from chronic pain may benefit from learning adaptive coping strategies. Consensus on efficient strategies for this group of patients is, however, lacking, and previous studies have shown inconsistent results. The present study has examined coping strategies in two distinctly different groups of chronic pain patients and a group of healthy controls. Thirty neuropathic pain (NP) patients, 28 fibromyalgia (FM) patients, and 26 pain-free healthy controls completed the Coping Strategy Questionnaire (CSQ-48/27) and rated their daily pain. The results showed that FM and NP patients did not cope differently with pain. The only difference between the groups was that FM patients felt more in control of their pain than NP patients. Both patient groups used more maladaptive/passive coping strategies, but surprisingly also more adaptive/active coping strategies than healthy controls. However, FM patients with high levels of passive strategies felt less in control than FM patients with low levels of passive strategies. This was not seen in NP patients. An important implication for clinical practice is therefore that passive coping strategies should be restructured into active ones, especially for FM patients. Otherwise, the same psychological treatment model can be applied to both groups since they use similar coping styles.

Cardiac Arrest following a Myocardial Infarction in a Child Treated with Methylphenidate.

The use of psychostimulants labeled to treat attention deficit/hyperactivity disorder increases. Among side effects these drugs raise blood pressure and heart rate, and the safety has been scrutinised in recent years. Data from large epidemiological studies, including over a million person-years, did not report any cases of myocardial infarction in current users of methylphenidate, and the risk of serious adverse cardiac events was not found to be increased. We present a case with an 11-year-old child, treated with methylphenidate, who suffered cardiac arrest and was diagnosed with a remote myocardial infarction. This demonstrates that myocardial infarction can happen due to methylphenidate exposure in a cardiac healthy child, without cardiovascular risk factors.

A validation study of the psychometric properties of the Groningen Reflection Ability Scale.

BACKGROUND: Reflection, the ability to examine critically one's own learning and functioning, is considered important for 'the good doctor'. The Groningen Reflection Ability Scale (GRAS) is an instrument measuring student reflection, which has not yet been validated beyond the original Dutch study. The aim of this study was to adapt GRAS for use in a Danish setting and to investigate the psychometric properties of GRAS-DK. METHODS: We performed a cross-cultural adaptation of GRAS from Dutch to Danish. Next, we collected primary data online, performed a retest, analysed data descriptively, estimated measurement error, performed an exploratory and a confirmatory factor analysis to test the proposed three-factor structure. RESULTS: 361 (69%) of 523 invited students completed GRAS-DK. Their mean score was 88 (SD = 11.42; scale maximum 115). Scores were approximately normally distributed. Measurement error and test-retest score differences were acceptable, apart from a few extreme outliers. However, the confirmatory factor analysis did not replicate the original three-factor model and neither could a one-dimensional structure be confirmed. CONCLUSIONS: GRAS is already in use, however we advise that use of GRAS-DK for effect measurements and group comparison awaits further review and validation studies. Our negative finding might be explained by a weak conceptualisation of personal reflection.

Differential pain modulation in patients with peripheral neuropathic pain and fibromyalgia.

Background The definition of neuropathic pain has recently been changed by the International Association for the Study of Pain. This means that conditions such as fibromyalgia cannot, as sometimes discussed, be included in the neuropathic pain conditions. However, fibromyalgia and peripheral neuropathic pain share common clinical features such as spontaneous pain and hypersensitivity to external stimuli. Therefore, it is of interest to directly compare the conditions. Material and methods In this study we directly compared the pain modulation in neuropathic pain versus fibromyalgia by recording responses to a cold pressor test in 30 patients with peripheral neuropathic pain, 28 patients with fibromyalgia, and 26 pain-free age-and gender-matched healthy controls. Patients were asked to rate their spontaneous pain on a visual analog scale (VAS (0-100 mm) immediately before and immediately after the cold pressor test. Furthermore the duration (s) of extremity immersion in cold water was used as a measure of the pain tolerance threshold, and the perceived pain intensity at pain tolerance on the VAS was recorded on the extremity in the water after the cold pressor test. In addition, thermal (thermo tester) and mechanical stimuli (pressure algometer) were used to determine sensory detection, pain detection, and pain tolerance thresholds in different body parts. All sensory tests were done by the same examiner, in the same room, and with each subject in a supine position. The sequence of examinations was the following: (1) reaction time, (2) pressure thresholds, (3) thermal thresholds, and (4) cold pressor test. Reaction time was measured to ensure that psychomotoric inhibitions did not influence pain thresholds. Results Pain modulation induced by a cold pressor test reduced spontaneous pain by 40% on average in neuropathic pain patients, but increased spontaneous pain by 2.6% in fibromyalgia patients. This difference between fibromyalgia and neuropathic pain patients was significant (P < 0.002). Fibromyalgia patients withdrew their extremity from the cold water significantly earlier than neuropathic pain patients and healthy controls; however, they had a higher perceived pain intensity on the VAS than neuropathic pain patients and control subjects. Furthermore, neuropathic pain patients had a localized hypersensitivity to mechanical and thermal stimuli in the affected area of the body. In contrast, fibromyalgia patients displayed a general hypersensitivity to mechanical and thermal stimuli when the stimuli were rated by the VAS, and hypersensitivity to some of the sensory stimuli. Conclusions These findings are the first to suggest that a conditioning stimulus evoked by a cold pressor test reduced spontaneous ongoing pain in patients with peripheral neuropathic pain, but not in fibromyalgia patients when directly compared. The current study supports the notion that fibromyalgia and neuropathic pain are distinct pain conditions with separate sensory patterns and dysfunctions in pain-modulating networks. Fibromyalgia should therefore not, as sometimes discussed, be included in NP conditions. Implications On the basis of the findings, it is of interest to speculate on the underlying mechanisms. The results are consistent with the idea that peripheral neuropathic pain is primarily driven from damaged nerve endings in the periphery, while chronic fibromyalgia pain may be a central disorder with increased activity in pain-facilitating systems.

[Higher prevalence of depression in patients with rheumatoid arthritis--a systematic review]. / Øget forekomst af depression hos patienter med reumatoid artritis.

Chronic pain patients frequently suffer from depression. This systematic review finds that patients suffering from rheumatoid arthritis (RA) have a higher prevalence of depression than controls without RA. Depression is related to pain intensity, passive coping strategies and disability. For patients this may result in a decreased quality of life and a shorter lifespan. For society it results in increased health costs.