Psychogenic Pain Research Articles

Біль і депресія: нові можливості фармакотерапії хронічних психогенних больових синдромів

У статті розглянуті сучасні погляди на проблему хронічного психогенного болю і його взаємозв’язку з депресивними розладами. З цього погляду проаналізовані вимоги до вибору оптимального фармакологічного інструменту в рамках комплексної терапії психогенного болю й депресії. Особливу увагу приділено механізмам дії та особливостям клінічного застосування дулоксетину (Дюлок) — антидепресанта з унікальними механізмами дії і клініко-фармакологічними властивостями, що дозволяють реалізувати стратегію патогенетично обгрунтованої фармакотерапії при депресії і хронічних психогенних больових синдромах. Детально розглянуті клінічна ефективність дулоксетину (Дюлок), його характеристики безпеки й рекомендації щодо практичного застосування препарату.

Self-perceived competence of dental students regarding the management of orofacial pain: a cross-sectional study

BackgroundThere is limited data on Pakistani dental students perceived competence in managing orofacial pain (OFP). This study aims to evaluate dental students self-perceived competence regarding the management of orofacial pain.MethodsThis cross-sectional study was conducted in Karachi at randomly selected two public and four private dental schools. This survey was conducted online from November 2020 to December 2020 in six dental schools. A questionnaire link was sent to the 475 students. A chi-square test and independent-sample t-test were conducted to assess the frequency distribution and compare mean scores of knowledge, diagnosis, and management parameters.ResultsOf the 475 students, 280 students filled the online survey leaving a response rate of 59%. A significant number of fourth-year students, 65 (51%, p = 0.005), feels knowledgeable regarding neuropathic pain compared to third-year students. The majority of the fourth-year students, 100 (78%, p = 0.010), feel comfortable managing intraoral pain. Almost all the students reported thinking that they need more knowledge related to five types of OFP. The fourth-year students had high mean scores related to knowledge, comfort in diagnosing and managing OFP categories.ConclusionThis study found that dental students perceived competence regarding orofacial pain management varies in relation to specific categories, being lowest for psychogenic pain.

Pain Conditions and Suicide Attempts in Military Veterans: A Case-Control Design

Specific pain conditions such as back pain and migraines are associated with increased risk of suicide mortality after accounting for key covariates. The purpose of the current study was to assess the associations of specific pain conditions with suicide attempts. Case-control. Veterans Health Administration (VHA). Individuals who utilized VHA services with a record of a suicide attempt (N = 30,051) in Fiscal Years 2013 and 2014 were identified and propensity score matched with controls with no such record (N = 30,051). Data on pain condition diagnoses (back pain, arthritis, migraine, headaches, psychogenic pain, neuropathy, fibromyalgia) psychiatric diagnoses, medical comorbidity, and demographics were extracted from VHA medical record and suicide surveillance datasets. Unadjusted logistic regression analyses found that each of the pain conditions were associated with suicide attempts (e.g., back pain: Odds ratio [OR]=3.25, 95% Confidence Interval [CI]=3.12-3.39). After adjusting for mental health conditions, medical comorbidity, and each of the pain conditions, the effects were attenuated across pain conditions; however, remained significant for each of the pain conditions except for fibromyalgia. Specifically, back pain (OR = 1.25, 95% CI = 1.19-1.32), migraines (OR = 1.29, 95% CI = 1.14-1.46), headaches (OR = 1.33, 95% CI = 1.19-1.48), and neuropathic pain (OR = 1.52, 95% CI = 1.33-1.74) were each associated with increased odds of a suicide attempt. Fibromyalgia was the only pain condition associated with re-attempt status (OR = 1.25, 95% CI = 1.08-1.45). Specific pain conditions are associated with increased odds of suicide attempts even after including key covariates. Limitations of the study include the retrospective study design and lack of examination into additional variables including prescription opioid use, pain intensity, and pain duration. The case-control design also limits the ability to draw causal or temporal conclusions.

Psychogenic pain as imaginary pain

Abstract: Psychogenic pain is considered to be pain that has a psychological origin. In this paper, I provide a brief history of the ways in which such pain has been interpreted and classified, highlighting the problem that psychogenic pain is typically defined by excluding organic evidence that could account for the sufferer’s experience. This has led to ambiguous disease classifications, which challenges the authenticity of the patient’s suffering. Today psychogenic pain is no longer considered a valid diagnosis, because it is deemed to stigmatize the patient by implying that their pain is imaginary. But such stigmatization continues in the modern approach to chronic pain. Addressing this issue requires us to understand the relationship between “emotional” and “physical” pain and acknowledge the reality of all suffering. Radden tackles these issues by showing that even though pain and suffering can be accompanied by mistaken beliefs, such experiences cannot be delusional. Keywords: Psychogenic Pain; Imaginary Pain; Chronic Pain; IASP; DSM Dolore psicogeno e dolore immaginario Riassunto: Con dolore psicogeno si intende un dolore di origine psicologica. In questo lavoro presento una breve storia delle interpretazioni e classificazioni di questa forma di sofferenza, evidenziando che queste si sono fondate perlopiu sull’esclusione di evidenze organiche a giustificazione dell’esperienza del sofferente. Cio ha portato ad ambigue classificazioni di malattia che mettono in discussione l’autenticita della sofferenza del paziente. Oggi, quella di dolore psicogeno non e piu considerata una diagnosi valida perche ritenuta stigmatizzante, implicando che il dolore del paziente sia immaginario. Ciononostante, la stigmatizzazione persiste nell’approccio odierno al dolore cronico. Affrontare questo problema comporta la comprensione della relazione tra dolore “emozionale” e dolore “fisico” ed il riconoscimento della realta di tutte le forme di sofferenza. Nel suo lavoro, Radden esamina queste tematiche mostrando che, sebbene esperienze di dolore e sofferenza possano essere accompagnate da credenze errate, le esperienze stesse non possono essere illusorie. Parole chiave: Dolore psicogeno; dolore immaginario; dolore cronico; IASP; DSM

Co-Players in Chronic Pain: Neuroinflammation and the Tryptophan-Kynurenine Metabolic Pathway.

Chronic pain is an unpleasant sensory and emotional experience that persists or recurs more than three months and may extend beyond the expected time of healing. Recently, nociplastic pain has been introduced as a descriptor of the mechanism of pain, which is due to the disturbance of neural processing without actual or potential tissue damage, appearing to replace a concept of psychogenic pain. An interdisciplinary task force of the International Association for the Study of Pain (IASP) compiled a systematic classification of clinical conditions associated with chronic pain, which was published in 2018 and will officially come into effect in 2022 in the 11th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11) by the World Health Organization. ICD-11 offers the option for recording the presence of psychological or social factors in chronic pain; however, cognitive, emotional, and social dimensions in the pathogenesis of chronic pain are missing. Earlier pain disorder was defined as a condition with chronic pain associated with psychological factors, but it was replaced with somatic symptom disorder with predominant pain in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) in 2013. Recently clinical nosology is trending toward highlighting neurological pathology of chronic pain, discounting psychological or social factors in the pathogenesis of pain. This review article discusses components of the pain pathway, the component-based mechanisms of pain, central and peripheral sensitization, roles of chronic inflammation, and the involvement of tryptophan-kynurenine pathway metabolites, exploring the participation of psychosocial and behavioral factors in central sensitization of diseases progressing into the development of chronic pain, comorbid diseases that commonly present a symptom of chronic pain, and psychiatric disorders that manifest chronic pain without obvious actual or potential tissue damage.

Psychosomatic Pain? The Meanings of Musculoskeletal Affliction in Finnish Medicine, ca. 1950–2000

Abstract In recent decades, pain has received extensive attention from historians. However, the boundary work between organic and psychogenic pain has been less studied. To address the mind–body problem in the history of pain, this article examines how Finnish physicians in the latter half of the twentieth century have applied the psychosomatic framework to three painful conditions: rheumatoid arthritis, chronic backache and fibromyalgia. Through the interrelated case studies, it is argued that the medical discussion on musculoskeletal pain reflected social and economic interests and values that evolved in the course of the twentieth century. The psychogenic illness explanation compelled physicians to step outside the confines of biomedical rationale. Therefore, the descriptions of the ‘mind’ behind the ‘body’ render conspicuous for historians the values, moral norms and social expectations that underlie biomedicine.

Pain, depression and anxiety: is there a light at the end of the tunnel?

In the present paper a modern sights to problem of chronic psychogenic pain and its relation to depressive and anxiety disorders have been looked. Based on this point of view, the requirements to choice of optimal pharmacological tool within complex therapy of psychogenic pain, depression and anxiety have been analyzed. A main attention paid to mechanisms of action and peculiarities of clinical use of drugs: duloxetine (Revival) – antidepressant from SNRI group with unique mechanisms of action and clinico-pharmacological properties, which make possible to realize the on-time impact on the mechanisms of development of depression and psychogenic pain; and pregabaline (Ligato) – drug from the anticonvulsants group, which influenced on universal mechanisms of cell ionic permeability at anxiety disorders and psychogenic pain. A clinical efficacy of duloxetine (Revival) and pregabaline (Ligato), its safety characteristics, and recommendations of practical use have been looked in detail.

P36: SOMATIC SYMPTOM DISORDER (SSD) AND ABDOMINAL PAIN: INCREASED OPIOID PRESCRIBING IN SURGICAL PATIENTS

Abstract Introduction Undifferentiated pain, and pain out of proportion of diagnosed pathology are sources of frustration to clinician and patient. SSD is a DSM-V diagnosis that has consolidated the previous diagnoses of psychogenic pain. It is a health anxiety condition, where sufferers experience multiple somatic symptoms which cause anxiety and distress. This anxiety results in frequent ED and GP presentations, extensive investigations, and increased opioid prescription. However, opioids do little to alleviate symptoms. Treatment should focus on underlying anxiety and depression. Population studies show SSD prevalence to be 15-20%, however SSD has never been studied in the surgical population. We hypothesized that the rates of SSD in the surgical population reflects that in primary care, and that SSD sufferers are more likely to be prescribed opioid analgesia. Method Adult patients admitted with abdominal pain of any non-traumatic aetiology to the Acute General Surgical Unit at a major tertiary hospital are being screened for SSD using the PHQ-15 questionnaire, and opioid prescription is being recorded. Result 400 participants have been recruited with a total SSD prevalence of 20%. Opioid prescribing rises sharply with SSD diagnosis. The average opioid prescription appears to be 3 times higher in patients with SSD compared to those without. Conclusion Our data confirms an SSD prevalence of 20% in the surgical population. This is associated with increased opioid prescription. Early recognition of SSD and implementation of appropriate treatment could reduce hospital presentations, admissions and opioid prescription. We will continue recruitment to 800 participants by March 2020. Take-home message SSD is common in all populations, and results in increased hospital presentations, admissions and opioid prescription. Early recognition and implementation of appropriate treatment may reduce healthcare burden, improve patient outcomes, and reduce opioid prescription.

Physical pain – suicidality association in adults: A meta-analysis

IntroductionMultiple epidemiologic and clinical studies have explored the relationship between physical pain and suicidal thoughts and behaviours.ObjectivesThe aim of this meta-analysis was to provide an update of the data already present in literature about this specific association in adults.MethodsStarting from a meta-analysis published by Calati and colleagues in 2015, 28 studies were included in this work. After searching on Pubmed (until March 2020), data were extracted from articles comparing the rates of current and lifetime suicidal thoughts and behaviours (death wish, suicidal ideation, suicidal planning, suicide attempt and suicide death: DW, SI, SP, SA, and SD) in adults with any type of physical pain and in individuals who did not report this condition. Data were analysed using Cochrane Collaboration Review Manager software (RevMan, version 5.4).ResultsAlthough high between-study heterogeneity was detected in most analyses, results suggested that adults with physical pain are more likely to report any form of suicidal outcome, except for death by suicide, compared to individuals not affected by pain. No evidence of publication bias was reported in the main analysis (lifetime SA).ConclusionsCollected data are therefore in line with previous literature on this topic, which considered physical pain an extremely relevant risk factor for suicidal thoughts and behaviours. Future studies should specifically focus on alternative types of physical pain (such as medically unexplained pain or psychogenic pain) or explore the different impact of acute versus chronic pain in terms of increased suicide risk.

Low Back Pain Diagnostic Approach

Low back pain is one of the leading causes of primary care and emergency room visits and job-related disability in many countries [1]. Back pain is sorted into three categories, differentiated by the duration of symptoms. Acute back pain, which is the focus of this article, is classified as pain lasting 6 weeks or less, subacute back pain is pain that has been present between 6 and 12 weeks, and chronic back pain is pain that persists longer than 12 weeks. Etiologies of low back pain include (but are certainly not limited to) mechanical injury (e.g., muscle sprain or spasm, ligament strain, facet joint disruption), arthritis, sciatica (lumbar radiculopathy), spinal fracture, malignancy, connective tissue disease, infection (e.g., vertebral osteomyelitis, epidural abscess), cauda equina syndrome, metabolic causes (e.g., hyperparathyroidism), abdominal or retroperitoneal visceral or vascular processes, psychogenic pain, and malingering. Careful history-taking and physical examination are crucial to diagnosing the etiology of back pain. This review presents the current state of science regarding the diagnosis and treatment of low back pain.

Diagnosis and treatment of low back pain in old patients

The back pain is one of the most common and socially significant neurological syndromes, leading to limited mobility and household independence of elderly patients. Specific «serious» causes of back pain account for 1-2% of all cases of back pain, approximately 10% of cases of pain correspond to radiculopathy, while the rest of the most common variants is related to nonspecific axial back pain. In the most cases of back pain, a clear connection between degenerative-dystrophic changes in the spine and the clinical manifestations and intensity of back pain is absent. On the other hand, dystrophic changes in the spine, which under certain conditions can be a source of chronic pain, cannot be completely ignored. Therefore, «osteochondrosis» is currently considered as a heterogeneous cascade process with the different course variations. In practice, it is not always possible to draw a line between nociceptive, neuropathic, nociplastic and psychogenic pain, more often in this case we can talk about a mixed nature of pain. Unreasonable neuroimaging with the identification of «accidental» findings can complicate the interpretation of the causes of pain, however, it is absolutely indicated to exclude serious specific diseases, spinal stenosis, when determining the indications for surgery. The presence of comorbid affective disorders, certain personality characteristics of patients contributes to the persistent nature of low back pain, therefore it is important to take these factors into account when diagnosing the causes and treatment of pain. Along with conventional anti-inflammatory drugs and other analgesics with a proven effect in the complex treatment of patients with degenerative-dystrophic changes in the spine with radicular and non-root pain syndromes, Symptomatic Slow-Acting Drugs in Osteoarthritis can be recommended.

Does the Breast Size in Females Correlate with the Severity of Mechanical Low Back Pain?

Background: Large breast is postulated to cause undue tension in the paraspinal muscles and may result in back pain. Improved pain score following mammaplasty supports this assertion. Such a question has not been evaluated in an indigenous black population. Objectives: To assess the correlation between the breast cup size and the severity of low back pain among women with mechanical low back pain. Method: This was a prospective cohort study. Eighty-four women with chronic backpain attending the Orthopaedic clinic participated excluding psychogenic back pain. The breast cup sizes were estimated from the difference between the bust and band sizes measured with an inelastic tape. The severity of pain was determined with the Oswestry disability index (ODI) data analysed with IBM SPSS version 26. Results: The mean age was 49.35 years. The predominant breast cup size was A, (88%), while the largest cup size was C. The mean duration of symptoms and ODI score was 3.33 months (SD = 2.63), and 42.30 (SD = 16.98) respectively. The breast cup size did not show a positive correlation with ODI score, r = ?0.021, p = 0.846. Conclusion: The severity of mechanical low back pain does not correlate with the breast cup size.

Implementation of a multimodal analgesia protocol in a burn patient in the emergency department

Introducton: Survival post-severe burn has increased significantly, and prognosis is not limited to survival or functionality, but extends to ensuring a pain-free quality of life. Pain management is one of the most crucial challenges in the care of severely burnt patients and includes pharmacological and non-pharmacological methods. Methods: Pain management report of a burn patient in the emergency department. Results: A 37-year-old male patient was admitted to the emergency department with hands, lower extremities, perineum and lower abdomen burns, after an explosion of a tank and leakage of steam and chemicals. The burn injury of partial thickness occupied about 25% of the total body surface. During the initial ABCDE assessment no life-threatening condition was found and attention was focused on pain management (reported VAS score 10). Wet gauges were applied to the burn area and paracetamol 1 gr, morphine 10 mg (in increments), pethidine 100mg, ketamine 60 mg, dexamethasone 8 mg, parecoxib 40 mg and midazolam 3 mg were administered intravenously, without significant improvement. A PCA pump with simultaneous continuous infusion and on-demand boluses of a solution of morphine, ketamine, lidocaine and midazolam was used, resulting in pain improvement (VAS score 5/10). Analgesia with PCA and systemic administration of paracetamol was continued in ward, where the patient stayed for 24 hours steadily improving (VAS score 4/10). On the 2nd day decision was made to transfer the patient to a specialised burn centre. Conclusions: Burn pain is complex and unpredictable, with features of nociceptive, psychogenic and neuropathic pain, including a strong element of hyperalgesia. Unfortunately, despite recognizing the importance of analgesia in the management of burns, such patients are often undertreated in the emergency department. Continuous pain reassessment and recording and the application of individualized multimodal analgesia protocols are required, with emphasis placed on the use of PCA pumps in a monitored care unit.

Management of pain in colorectal cancer patients.

In this review we focus on the pathophysiology of CRC-related pain and discuss currently applied pain management. Pain is a symptom reported by over 70 % of colorectal cancer (CRC) patients. It remains a feared and debilitating consequence of both cancer and cancer-related treatment. There are many options for pain management in CRC, consisting of intravenous, oral or topical medications. In order to address the full spectrum of pain, proper treatment should address the nociceptive, neuropathic and/or psychogenic pain component. Currently available methods do not bring pain relief to satisfying number of patients and, if used improperly, can cause a number of complications. Therefore, future treatments should focus primarily on alleviating pain, but also on reducing possible side effects. In this article we cover recent and promising pharmacological and non- pharmacological developments emerging in the field of CRC treatment.

Speech stress recognition using semi-eager learning

Homo-sapiens suffer from psychogenic pain due to current day lifestyle. According to psychologists, stress is the most destructive form of psychalgia and it is a vicious companion for this species. Immoderate levels of stress may lead to the death of many individuals. Normally, the presence of stress gives rise to certain emotions which can be detected to predict stress levels of a person. This paper proposes the development of mechanized and efficient Speech Emotion Recognition (SER) for stress level analysis. The paper investigates the performance of perceptual based speech features like Revised Perceptual Linear Prediction Coefficients, Bark Frequency Cepstral Coefficients, Perceptual Linear Predictive Cepstrum, Gammatone Frequency Cepstral coefficient, Mel Frequency Cepstral Coefficient, Gammatone Wavelet Cepstral Coefficient and Inverted Mel Frequency Cepstral Coefficients on SER. The novelty of this work involves application of a SemiEager (SemiE) learning algorithm for evaluating auditory cues. SemiE offers advantages over eager and lazy based learning by reducing the computational cost. Stress level recognition being the main objective, the Speech Under Simulated and Actual Stress (SUSAS) benchmark database is used for performance analysis. A comparative analysis is presented to demonstrate the improvement in the SED performance. An overall accuracy of 90.66% recognition of stress related emotions is achieved.

Zastosowania terapeutyczne mianseryny

The article presents data on the therapeutic uses of mianserin. Mianserin has been used successfully for many years to treat depression, but it seems that its potential could be better exploited. A case report was also provided regarding a patient with psychogenic pain and depression who was successfully treated with mianserin.

A hidden mesencephalic variant of central pain

Central post-stroke pain (CPSP) can arise after lesions anywhere in the central somatosensory pathways, essentially within the spinothalamic system (STS). Although the STS can be selectively injured in the mesencephalon, CPSP has not been described in pure midbrain infarcts. Of more than 300 CPSP consecutive cases, we describe five patients who developed definite neuropathic pain following lesions circumscribed to the postero-lateral mesencephalon. The mesencephalic lesion responsible for pain was always haemorrhagic and always involved the spinothalamic tract (STT), as demonstrated by suppressed laser-evoked potentials in every case, with or without preserved lemniscal function. In three cases the midbrain injury could be ascribed to trauma, presumably from the cerebellar tentorium. As a result of the paucity of sensory symptoms, the pain was considered as 'psychogenic' in two of the patients until electrophysiological testing confirmed STT involvement. Postero-lateral midbrain lesions should be added to potential causes of CPSP. Because pain and spinothalamic deficits may be the only clinical sign, and because small lateral midbrain lesions may be difficult to trail with MRI, mesencephalic CPSP can be misdiagnosed as malingering or psychogenic pain for years. Selective spinothalamic injury caused by small lateral midbrain lesions is a very rare cause of central post-stroke pain that can remain undiagnosed for years. It appears to obey to haemorrhagic, sometimes post-traumatic lesions. Sudden development of contralateral burning pain with isolated spinothalamic deficits may be the only localizing sign, which can be easily objectively detected with electrophysiological testing.

Psychological Morbidity and Chronic Disease Among Adults With Traumatic Spinal Cord Injuries: A Longitudinal Cohort Study of Privately Insured Beneficiaries

ObjectiveTo compare the longitudinal incidence of psychological morbidities and multimorbidity and estimates of chronic diseases among adults with spinal cord injuries (SCIs) as compared with adults without SCIs. MethodsPrivately insured beneficiaries who had medical coverage at any time between January 1, 2001, and December 31, 2017 were included if they had an International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic code for a traumatic SCI (n=6,847). ResultsAdults with SCIs (n=6847) had a higher incidence of adjustment reaction (7.2% [n=493] vs 5.0% [n=42,862]), anxiety disorders (19.3% [n=1,322] vs 14.1% [n=120,872]), depressive disorders (29.3% [n=2,006] vs 9.3% [n=79,724]), alcohol dependence (2.4% [n=164] vs 1.0% [n=8,573]), drug dependence (2.3% [n=158] vs 0.8% [n=6,858]), psychogenic pain (1.0% [n=69] vs 0.2% [n=1,715]), dementia (6.5% [n=445] vs 1.5% [n=12,859]), insomnia (10.9% [n=746] vs 7.2% [n=61,722]), and psychological multimorbidity (37.4% [n=2,561] vs 23.9% [n=204,882]) as compared with adults without SCIs (n=857,245). The adjusted hazard ratios (HRs) of each psychological outcome were significantly higher for individuals with SCI and ranged from 1.18 (95% CI, 1.08-1.29) for anxiety disorders to 3.32 (95% CI, 1.93-5.71) for psychogenic pain. Adults with SCIs also had a significantly higher prevalence of all chronic diseases and chronic disease multimorbidity (51.1% vs 14.1%), except human immunodeficiency virus infection/AIDS. After propensity matching for age, education, race, sex, and chronic diseases (n=5884 matched pairs), there was still a significantly higher incidence of most psychological disorders and psychological multimorbidity among adults with SCIs. ConclusionAdults with traumatic SCIs experienced an increased incidence of psychological morbidities and multimorbidity as compared with adults without SCIs. Clinical efforts are needed to improve mental health screening and targeted interventions to reduce the risk for psychological disease onset in the traumatic SCI population.

Aberrant Thalamic-Centered Functional Connectivity in Patients with Persistent Somatoform Pain Disorder.

PurposeRecent task-based fMRI studies have shown that Persistent Somatoform Pain Disorder (PSPD) patients demonstrated aberrant activity in a wide range of brain regions associated with sensation, cognition and emotion. However, these specific task-based studies could not clearly uncover the alterations in the spontaneous brain networks that were associated with the general pain-related symptoms in PSPD.Patients and MethodsIn the present study, 13 PSPD patients and 23 matched healthy controls (HCs) were enrolled. Resting state and 3D structural imaging data were collected during magnetic resonance imaging (MRI) scans. Ninety regions of interest (ROIs) were selected from the automated anatomical labeling (AAL) template. The functional connectivity toolbox “CONN” was used to calculate the functional connectivity (FC) coefficients.ResultsOur results showed that PSPD patients exhibited increased FCs between the left thalamus and the right amygdala, the right hippocampus, and multiple sub-regions of the occipital lobe when compared to HCs. Correlation analysis revealed a negative correlation between the left thalamus-right amygdala FC and the level of anxiety in PSPD patients.ConclusionThese findings suggest that the altered FC between thalamus and amygdala may be the neural mechanisms underlying the pain-related anxiety in PSPD.

Burning Mouth Syndrome and Nociplastic Pain

Burning mouth syndrome （BMS） is classified into chronic primary orofacial pain. Chronic primary pain syndrome is characterized by nociplastic pain in which pain arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain. Historically, these types of pain have been regarded as psychogenic pain. Recent studies have revealed that chronic primary pain syndrome including BMS shows dysfunction of the pain modulatory system, especially descending pain inhibition. This altered brain function can be monitored by neurophysiologic tests including quantitative sensory testing and conditioned pain modulation （CPM） in combination with imaging modalities. These research modalities have revealed that the brain in BMS patients shows temporal summation of activity in areas associated with pain modulation during tonic noxious hot stimulation of the lower lip and temporal suppression of activity in these areas by repeated noxious stimuli without perceptional pain habituation. Further, there are reports in the literature of facilitated pain response to heat and our experimental data have revealed the lack of CPM in BMS patients. The results of previous studies have suggested that dysfunction in the dopaminergic neural system is involved in altered pain modulating function.