Chronic Idiopathic Pain Syndromes Research Articles

'That's what makes me better': Investigating children and adolescents' experiences of pain communication with healthcare professionals in paediatric rheumatology.

Pain communication should be an integral part of clinical consultations, particularly in paediatric rheumatology where children and adolescents frequently present with chronic musculoskeletal pain. To date, literature exploring the nature of and extent to which pain communication occurs has focused on healthcare professionals as respondents, yielding inconsistent and incomplete findings. The aim of this study was to explore children and adolescents' experiences of pain communication in the context of paediatric rheumatology consultations. Data were collected using semi-structured telephone interviews with children and adolescents recruited from three tertiary paediatric rheumatology centres in the United Kingdom. A framework analysis approach was used to explore the similarities and divergences in participant accounts. Twenty-six children and adolescents (aged 6-18 years, median=14, 58% female) participated. Diagnoses included: juvenile idiopathic arthritis, Chronic Idiopathic Pain Syndromes, Ehlers Danlos Syndrome/Hypermobility. Four themes were identified: (1) Co-ordination of pain communication; (2) Barriers to pain communication; (3) Facilitators of pain communication; (4) Dissatisfaction with pain communication. These themes particularly encompassed the process of communication, disclosure of effective and ineffective approaches and the impact of communication. Participants expected questions about pain, felt cared about and found talking about pain natural. Challenges included augmenting the feeling of being different to peers and concerns about management plans changing as a result of pain conversations. Children and adolescents recalled a range of effective and ineffective pain communication approaches. Our study informs recommendations which highlight how healthcare professionals can improve their communication about pain with children and adolescents in the future. Our findings demonstrate that children and adolescents attending paediatric rheumatology expect to be and value being asked about their pain during consultations with healthcare professionals. Children and adolescents remember many of the processes involved, experiences of and the outcomes of pain communication. The current study reveals insights which can improve healthcare professional pain communication with children and adolescents. Our study introduces key recommendations for healthcare professionals to have more effective pain conversations in future.

THE IMPACT OF ELECTIVE DIAGNOSTIC LAPAROSCOPY IN DIAGNOSING CHRONIC ABDOMINAL PAIN

Background: Chronic idiopathic pain syndromes are amongst the most challenging and demanding conditions to treat across the whole age spectrum. Despite these patients having undergone numerous diagnostic work ups, their pain remains a challenge to all known diagnostic and treatment methods. Objectives Of The Study: To study the advantages of diagnostic laparoscopy in identifying the etiology of undiagnosed chronic abdominal pain. Materials And Methods: Study Centre: Institute of General Surgery, Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai. October 2019 to October 2020. Single-center cross-sectionalDuration Of Study: Study Design: study. All the patients who came to general surgery OPD during my one-year study period 35 {n = Z2 1-α/2 P (1-P)Sample Size: /e2 P=3% e= 5% Z=1.96}. All cases of undiagnosed (by conventional methods and investigations such asInclusion Criteria: detailed history, clinical examination, blood counts, urine examination, USG abdomen, Plain x ray abdomen) chronic abdominal pain>3months duration of both sex. All cases of undiagnosed chronic abdominal pain in patients >14years of age. Cases of clinically diagnosed chronic abdominal pain of >3 months duration not responding to the treatment given. Exclusion Criteria: Results:Persons suffering from any kind of cognitive dysfunction are excluded from the study. All 35 patients underwent Diagnostic Laparoscopy under General anaesthesia after all the conventional investigations did not yield any diagnosis. 35 patients in the age group of 15 – 69 years were involved in the study with the average age of presentation being 35 years. 66% of the study population were females. The most common nding at laparoscopy in our study was postoperative adhesions (51.42%). It was followed by patients who had a normal abdominal nding at laparoscopy (17.14 %) and recurrent appendicitis in 14.28 %. The average duration of hospital stay being 5.5 days. Therapeutic intervention done at the time of diagnosis relieved 70% of patients of their pain at the end of three months. DiagnosticInterpretation And Conclusion: laparoscopy has an effective diagnostic accuracy and therapeutic efcacy in the management of patients who present to us with chronic abdominal pain especially in whom conventional methods of investigations have failed to elicit a cause for the pain. Ability to pin point a cause for the abdominal pain or exclude a more major cause for pain not only avoids further investigations but also plays a signicant role in alleviating the fears in the minds of the patients. Laparoscopy prevents unnecessary laparotomy in a signicant number of cases. Diagnostic laparoscopy has a denitive role in the management of patients with chronic pain abdomen and should be an important investigative tool in the armamentarium of all practicing surgeons.

Characterizing pain flares in adolescent inflammatory and non-inflammatory musculoskeletal disorders: A qualitative study using an interpretative phenomenological approach.

Adolescents with musculoskeletal disorders experience acute exacerbations in pain, colloquially called "pain flares" in adult literature. This study aimed to explore adolescents' lived experience of pain flares, including what pain flares are, why they occur, how they are managed and what lasting effects they have on adolescents. A sample of 10 adolescents diagnosed with juvenile idiopathic arthritis or chronic idiopathic pain syndrome were recruited from a tertiary hospital in the UK. Data were collected using semi-structured interviews and visual aids, and analysed using interpretative phenomenological analysis. Four broad themes were identified which describe as a journey of change from participants: (a) daily life with pain, where adolescents report a level of pain that is "normal" for them which they can tolerate and continue their daily routines around; (b) pre-flare period, where adolescents begin to notice pain increasing beyond normal levels and employ preventative strategies to reduce the risk of symptoms developing into a flare; (c) flare period, where adolescents describe the symptoms, frequency, duration, impact and their attempts to manage flares; to their (d) post-flare period, where symptoms begin to return to baseline levels and adolescents take actions to regain the level of normality experienced in daily life. This study has identified a number of components of the pain flare experience. Findings show that pain flares are more than an increase in pain intensity; they are multi-layered and require other features to change. These findings help to differentiate pain flares from typical fluctuations in pain.

A study on the impact of elective diagnostic laparoscopy in diagnosing chronic abdominal pain

Background: Chronic idiopathic pain syndromes are amongst the most challenging and demanding conditions to treat across the whole age spectrum. Despite these patients having undergone numerous diagnostic work ups, their pain remains a challenge to all known diagnostic and treatment methods. Aims and Objectives: We aim to evaluate the diagnostic and therapeutic efficacy of laparoscopy in the management of such patients in this prospective study. Materials and methods: Thirty five patients with chronic pain abdomen were included in this study. The pain in all these patients was either of unclear etiology or not responding to the treatment given after clinical assessment and lasting for more than 3 months duration. Pain of shorter duration and patients less than 14 years of age were excluded from the study. All patients were subjected to diagnostic laparoscopy and procedure. The results were tabulated and analyzed. Results: Females were more affected by this condition and the most common site of pain being the peri -umbilical region. A definitive diagnosis was made per operatively in 29 patients (82.85%) while in the remaining 6 (17.14%), no obvious pathology was detected. The most common findings in our study was post-operative adhesions (50%), followed by recurrent appendicitis (13.33%), Carcinoma (5.71%), Mesenteric lymphadenopathy and Tuberculosis (2.85% each). Pain assessment done at 1 month follow up showed pain relief in 80.55% and 3 month follow up showed pain relief in 70% of patients. Conclusion: Post-operative adhesions form a majority of cause for causing chronic pain abdomen. Diagnostic laparoscopy is a safe and effective modality for the diagnostic and therapeutic management of such patients.

Role of diagnostic laparoscopy in chronic abdominal pain

Background: Chronic idiopathic pain syndromes are amongst the most challenging and demanding conditions to treat across the whole age spectrum. Despite these patients having undergone numerous diagnostic work-ups, their pain remains a challenge to all known diagnostic and treatment methods.Methods: To evaluate role of diagnostic laparoscopy in chronic abdominal pain a prospective observational study was done. The present study was conducted on patients with undiagnosed chronic abdominal pain coming to the Department of Surgery, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune. 75 patients with chronic abdominal pain who attend the General Surgery Department (OPD) were included in the study. Patients were included in the study after taking their voluntary informed consent. The categorical variables were assessed using Pearson chi-square. The quantitative variables were assessed using T-test. The test was considered significant only if the p value comes out to be less than 0.05.Results: Based on the findings of the study after performing diagnostic laparoscopy for 75 patients with chronic abdominal pain it was found that most common finding was of appendicitis (32%) followed by abdominal Koch’s (24%) and post-operative pain relief using VAS showed p value of less than 0.05 at 3 months of follow up post diagnostic laparoscopy.Conclusions: The present study concluded that laparoscopy is an effective diagnostic role in evaluating patients with chronic abdominal pain, in whom conventional methods of investigations have failed to elicit a certain cause. The advantage of diagnostic laparoscopy over non-invasive methods is the ability to perform therapeutic procedure at the same time in cases of chronic abdominal pain. Diagnostic laparoscopy is safe, cosmetically better and having less morbidity.

P36 Adolescents’ experiences of fluctuating pain in musculoskeletal disorders: a qualitative systematic review and thematic synthesis

Abstract Background Adolescents with chronic musculoskeletal pain experience pain that fluctuates within and across days. The aim of this review was to (i) synthesise the qualitative literature on adolescents’ experiences of fluctuating pain in musculoskeletal disorders, (ii) identify the concept of pain flare and how this may differ from daily fluctuation of pain, and (ii) identify knowledge gaps to inform the design of future research. Methods Six electronic databases (MEDLINE, EMBASE, PsycINFO, CINAHL, OpenGrey and Scopus) and reference lists of relevant articles were searched from inception to June 2018. Articles were eligible for inclusion if they were qualitative studies exploring the experiences of pain in adolescents, aged between 10–19 years, diagnosed with juvenile idiopathic arthritis (JIA) and chronic idiopathic pain syndromes (CIPS). Comprehensiveness of reporting was assessed using the Consolidated Criteria for Reporting Qualitative Health Research (COREQ) framework, and studies were analysed using thematic synthesis. Results Of the 3,787 records identified, 32 studies were included from 11 countries. 536 young people with JIA or CIPS participated in the studies, of which 509 had a diagnosis of JIA, and 27 with CIPS. Interviews were conducted in 29 studies, with 9 studies also combining interviews with focus groups, observations, questionnaires, researcher journaling, visual depictions and diaries. Although all included studies reported adolescent’s experience of pain, only 19 studies provide insight into the impact of fluctuating pain on an individual’s life and lived experience. 21 studies included data from parents, siblings, health professionals and/or individuals with other chronic illnesses, but efforts were made to only extract data referring to or expressed by adolescents with JIA or CIPS. Ages of patients ranged from 3 to 23 years, but all studies averaged within the adolescent range. Principal findings were synthesised under three themes: 1) symptom experience, 2) disruption and loss, and 3) regaining control. These themes can be seen to describe a journey through which the adolescent experiences fluctuating pain and associated symptoms, encounters the challenges to lifestyle that fluctuating pain presents, followed by employing coping strategies to regain a sense of control of their lives and pain. Each stage is experienced differently depending on individual factors such as adolescents’ developmental status, pain condition, and duration of the pain experience. Conclusion Adolescents with chronic musculoskeletal pain live with a daily background level of symptoms which frequently fluctuate and are associated with functional and emotional difficulties. It is not clear whether these symptoms and challenges are experienced as part of normal fluctuations in pain, or whether they reflect symptom exacerbations classified as flares. Further research is needed to explore the frequency and characteristics of pain flares, and how they differ from their normal fluctuations in pain. Conflicts of Interest The authors declare no conflicts of interest.

P37 Exploring the experience of pain flares in adolescent inflammatory and non-inflammatory musculoskeletal disorders: a phenomenological study

Abstract Background Adolescents with inflammatory and non-inflammatory rheumatic musculoskeletal disorders (RMD) experience acute exacerbations in pain, referred to as pain flares in the adult literature. But little remains known about what pain flares are, why they occur, how they are managed and what lasting effects they have during adolescence. This study explored the lived experience of pain flares in adolescents with RMD. Methods Adolescents with juvenile idiopathic arthritis (JIA) or chronic idiopathic pain syndromes (CIPS) were recruited from a UK tertiary paediatric and adolescent rheumatology centre. Data were collected using semi-structured interviews and visual aids, and analysed using interpretative phenomenological analysis. Results Participants were eight females and two males aged between 13 and 17 years (M = 14.7, SD = 1.25). Four participants had JIA and six had CIPS. All participants experienced periods when pain deviates from their usual variation in pain, but none reported using the term pain flare to describe these experiences. These experiences were conceptualised as a journey of change from their 1) daily life with pain, 2) pre-flare period, 3) flare period, to their 4) post-flare period. 1) In daily life, adolescents report a level of pain that is usual for them which they manage and continue their daily routines around. 2) Pain, at times, increased beyond usual levels and adolescents reported noticing when a pain flare was coming on (e.g. due to physical exertion). They employed strategies for managing the pre-flare period, however, if they did not succeed in preventing a flare, or when flares occurred without a trigger or controllable cause, pain began to intrude on their lives. 3) All pain flares were described as an increase in the intensity of their usual pain, and were also associated with an increase in the location, duration and/or quality of pain; an increase in other unpleasant symptoms such as fatigue, psychological symptoms, headaches and/or sickness; and a reduction in physical, emotional, cognitive and/or social functioning. The frequency of flares was variable, ranging from weekly flare events to less than two a year. Flares were generally short lived, lasting a few hours to a few days. The majority of flares were managed with parental input, with adolescents seeking medical support when a flare was perceived to be associated with infection in JIA. 4) As flares were brought under control, the pain returned to usual levels but the psychological symptoms outstayed the pain. Participants took actions to regain the level of normality experienced in daily life. Conclusion Participants had varying interpretations of what constitutes a flare, but the key finding was that flares are not only an increase in pain intensity, but other features are also required to change. These findings help to differentiate flares from normal variation in pain. Conflicts of Interest The authors declare no conflicts of interest.

Melatonin oral supplementation against fibromyalgia-related skeletal muscle alterations

Fibromyalgia is a chronic idiopathic pain syndrome characterized by widespread musculoskeletal pain and a deep range of other symptoms including disordered sleep, paresthesia, depression and anxiety (1). To date, its aetiopathogenesis and pathophysiology are still not understood, but the musculoskeletal, neuroendocrine and central nervous systems appear to play major roles in the development and progression of fibromyalgia (2). Important factors involved in the pathogenic process of fibromyalgia are oxidative stress and inflammation suggesting that antioxidative supplementation might be important in the management and modulation of fibromyalgia. Recent evidences suggest that melatonin may be suitable for this purpose. Melatonin is a small, highly conserved pineal indoleamine and due to its important and well known antioxidant and antinflammatory properties, together with also its analgesic effects, our research group studied the beneficial effects of the melatonin oral supplementation against the pathogenetic process of fibromyalgia. In detail, Sprague Dawley rats were randomly treated with reserpine, to reproduce the pathogenic process of fibromyalgia (3), and/or with melatonin (MelapureTM by Flamma S.p.A.). At the end of the treatments, the animals treated with reserpine showed moderate alteration at hind limb skeletal muscle level with difficult in moving, together with a significant expression of several oxidative stress and inflammatory markers at the gastrocnemius muscle level. Interestingly, melatonin, dose and time dependently, reduced the difficulties in walking and the musculoskeletal oxidative stress and inflammatory processes. In summary, this pilot study suggested that melatonin could be an in vivo effective tool against muscoloskeletal morphofunctional damages and dysfunctions in the management of fibromyalgia-related complications.Sincere thanks to Flamma S.p.A.- Italy (www.flammagroup.com) for courteously providing the melatonin and for the precious economic support to this study.

Dietary linoleic acid-induced alterations in pro- and anti-nociceptive lipid autacoids: Implications for idiopathic pain syndromes?

BackgroundChronic idiopathic pain syndromes are major causes of personal suffering, disability, and societal expense. Dietary n-6 linoleic acid has increased markedly in modern industrialized populations over the past century. These high amounts of linoleic acid could hypothetically predispose to physical pain by increasing the production of pro-nociceptive linoleic acid-derived lipid autacoids and by interfering with the production of anti-nociceptive lipid autacoids derived from n-3 fatty acids. Here, we used a rat model to determine the effect of increasing dietary linoleic acid as a controlled variable for 15 weeks on nociceptive lipid autacoids and their precursor n-6 and n-3 fatty acids in tissues associated with idiopathic pain syndromes.ResultsIncreasing dietary linoleic acid markedly increased the abundance of linoleic acid and its pro-nociceptive derivatives and reduced the abundance of n-3 eicosapentaenoic acid and docosahexaenoic acid and their anti-nociceptive monoepoxide derivatives. Diet-induced changes occurred in a tissue-specific manner, with marked alterations of nociceptive lipid autacoids in both peripheral and central tissues, and the most pronounced changes in their fatty acid precursors in peripheral tissues.ConclusionsThe present findings provide biochemical support for the hypothesis that the high linoleic acid content of modern industrialized diets may create a biochemical susceptibility to develop chronic pain. Dietary linoleic acid lowering should be further investigated as part of an integrative strategy for the prevention and management of idiopathic pain syndromes.

English

BACKGROUND: Chronic idiopathic pain syndromes are among the most challenging and demanding conditions to treat across the whole age spectrum. Potentially it can be unrewarding for both the patients and the medical team. Patients with chronic abdominal pain (CAP) can undergo numerous diagnostic tests with failure to detect any structural or biochemical abnormality. This study was undertaken to assess the diagnostic and therapeutic role of laparoscopy in patients with unexplained chronic abdominal pain (UCAP). PATIENTS AND METHODS: Diagnostic laparoscopy was performed for 100 patients with UCAP not diagnosed by usual clinical examination and investigations. The pain in all patients was of unclear etiology despite all the investigative procedures. All patients were subjected to laparoscopic evaluation for their conditions. The findings and outcomes of the laparoscopy were recorded and analyzed. RESULTS: UCAP is common in females (62%) than in males. The most frequent laparoscopic findings detected were abdominal adhesions (30%), followed by pelvic inflammatory disease (25%), abdominal tuberculosis (12%), chronic appendicitis (8%), mesenteric lymphadenitis (5%) and diverticulosis (2%). In 18% of cases no identifiable cause could be found. Follow after 2 months revealed pain relief in 84% irrespective of cause of pain. CONCLUSION: Laparoscopy is an effective diagnostic and therapeutic modality in the management of patients with chronic abdominal pain.

Chronic idiopathic pain syndromes

In this review, we outline a rational approach to the complex problem of chronic idiopathic pain syndromes. We focus principally on musculoskeletal pain disorders and emphasize the differences between adults and children. The different nomenclatures in use are clarified and the epidemiology is examined. The key clinical findings are highlighted and different therapeutic approaches are reviewed. The evidence base for the interventions reviewed include both 'medical' and 'non-medical' approaches. Practical problems and issues are dealt with throughout the review in order to construct a pragmatic approach that the authors intend to be of everyday use to the clinician and allied health professionals.

Education of general practitioners in psychosomatic medicine: Effects of a training program on the daily work at Swedish primary health care centers

Two interrelated studies are reported. One reports the results of a questionnaire interview with a reference group of 51 general practitioners. The respondents express a considerable dissatisfaction with their previous medical training as it concerns their knowledge of the psychosomatic medical paradigm. The other study evaluates the effects of a 5-year education program concerning psychodynamic theories and an integrative psychosomatic approach to treatment. Six general practitioners participated in this educational program, which included both theoretical seminars and practical training in psychotherapy (under supervision) with patients suffering from chronic idiopathic pain syndrome. All the participants reported developing substantial skill in treating such patients and in handling other kinds of patients with multifactorial etiology of symptoms. The participants of the training program did not initially differ from the larger reference group as to the previous knowledge and practice in integrative psychosomatic medicine, and it may be concluded that many physicians would profit from such postgraduate training. The self-reports of all these experienced physicians also indicate that there is too little theory and practice of the psychesoma interaction in the basic medical education.

The Thematic Apperception Test as an aid in understanding the psychodynamics of development of chronic idiopathic pain syndrome.

41 chronically ill low-back pain patients (27 women, 14 men) with a long history of work disablement (median = 2 years and 8 months) were submitted to thematic apperception testing (TAT). The tape-recorded protocols were evaluated by 2 independent, experienced clinicians well acquainted with the TAT, as well as with psychoanalytic theory and technique. The 2 evaluators judged almost all the patients as depressive, alexithymic, passive and antiaggressive with clear tendencies to reaction formation towards underlying aggressivity. Many patients were further judged as guilt-ridden with an unresolved oedipal conflict, while others had a deep oral problem with suicidal tendencies. Two of the patients were judged by both evaluators as having psychotic or prepsychotic traits. Overall interrater reliability was very high, with a correlation for the different categories between 0.50 and 0.76 (median 0.72 and p value never below 0.005). Our results indicate that one of the main characteristics of low-back pain patients is the denial of aggression. Other main features of our patients were depressivity, passivity and oral or oedipal conflicts, alexithymia and lack of internal locus of control. Also we find the TAT as a very suitable test for achieving the understanding of the complexity of the problem of pain.

Chronic Idiopathic Pain Syndrome

Chronic idiopathic pain syndrome is a common, disabling and costly condition. It is believed to be of psychological origin but may involve both cerebral and peripheral physiological mechanisms. It is often associated with depression. Its assessment and management need to be multifactorial, i.e., medical, psychosocial and psychiatric. A thorough initial medical assessment is crucially important in order to identify any organic contributory factors and to gain the patient's trust. It is also essential to carry out a psychosocial and psychiatric assessment so as to evaluate the role of psychological and socioeconomic factors and establish whether a diagnosable psychiatric disorder is present. The latter is most likely to be a depressive, anxiety, or somatoform disorder. If the medical assessment fails to come up with a plausible organic explanation for the patient's pain, he or she should be told so clearly. The patient should be told that the goal of the treatment is not to cure the pain but to help him/her improve his/her functioning and sense of control over pain and life generally. The type of management most likely to succeed in this goal is one that is multifactorial and comprehensive rather than focused on one treatment modality only.

Clomipramine and mianserin in chronic idiopathic pain syndrome

The reduction of pain by two antidepressants, clomipramine and mianserin, was, in this study on 253 patients with chronic idiopathic pain syndrome, found to be not better than a placebo when all patients were compared independently of the classification of pain. The improvement rate was around 40% after 6 weeks of treatment when using a 50% or better reduction in pain level. However, in patients who fulfilled a checklist definition of minor to major depression (30% of the total patient material) clomipramine was superior to mianserin and placebo with an improvement rate of 75% after 6 weeks. Using pain curves over time as outcome measure in the various clinical pain categories it was found that both mianserin and clomipramine seemed superior to placebo in patients with tension headache, but in patients with low back pain syndrome placebo was superior to the two antidepressants. No difference among the three treatments was found in patients with burning mouth syndrome or in patients with abdominal pain. These differences underline the importance of studying specific pain syndromes rather than composite groups of patients with idiopathic pain. The clinical significance of these pain curves needs further placebo controlled investigations.

Clomipramine and maprotiline in the treatment of chronic idiopathic pain syndromes; a comparison and biological markers

This article shortly summarizes results from a clinical trial in idiopathic pain syndromes. In order to evaluate the clinical effect of antidepressants in patients with idiopathic pain syndromes a noradrenaline reuptake inhibitor (maprotiline) and a serotonin reuptake inhibitor (clomipramine) were given to 70 patients for six weeks in a randomized double-blind multicentre trial. Eighteen patients were excluded during the study. In addition to pain, 16 depressive symptoms were observed. Clomipramine-treated patients showed an overall improvement of 63%, and maprotiline-treated patients reported a 36% improvement (p<0.05). Side effects were generally mild. Eight patients in the clomipramine group and one in the maprotiline group were excluded due to side effects. The 3H-imipramine receptor binding to platelets in chronic idiopathic pain patients was measured. The Bmax values were decreased by 11% prior to treatment. Maprotiline treatment tended to increase the values towards those of healthy controls, while...

Melatonin in serum and urine in patients with idiopathic pain syndromes

In 16 healthy volunteers, 16 patients with neurogenic pain syndromes, 37 patients with idiopathic pain syndromes, and 30 depressed patients, melatonin in serum was determined at 2 a.m. when the peak concentration was expected. In a somewhat larger series comprising 53 healthy volunteers, 14 patients with neurogenic pain syndromes, and 35 patients with idiopathic pain syndromes, melatonin was measured in urine collected during the night in a standardized manner. Chronic pain patients (with neurogenic or idiopathic pain disorders) and depressed patients had significantly lower melatonin in serum at 2 a.m. than healthy volunteers. Chronic pain patients also had significantly lower melatonin in urine than healthy volunteers, even when age, sex, and body weight were taken into account. The low melatonin concentrations were related to increased depressive symptomatology, especially sadness, bodily discomfort, inner tension, concentration difficulties, and pain. As low concentrations of melatonin in serum and urine also are found in patients with depressive disorders, the results are in line with the suggestion that the chronic idiopathic pain syndrome may be a variant of depressive disease, or the two syndromes may share a common pathogenic mechanism.