Mutsuhiro Nakao

Work-related stress and psychosomatic medicine

This article introduces key concepts of work-related stress relevant to the clinical and research fields of psychosomatic medicine. Stress is a term used to describe the bodys physiological and/or psychological reaction to circumstances that require behavioral adjustment. According to the Japanese National Survey of Health, the most frequent stressors are work-related problems, followed by health-related and then financial problems. Conceptually, work-related stress includes a variety of conditions, such as overwork, unemployment or job insecurity, and lack of work-family balance. Job stress has been linked to a range of adverse physical and mental health outcomes, such as cardiovascular disease, insomnia, depression, and anxiety. Stressful working conditions can also impact employee well-being indirectly by directly contributing to negative health behaviors or by limiting an individuals ability to make positive changes to lifestyle behaviors, such as smoking and sedentary behavior. Over the past two decades, two major job stress models have dominated the occupational health literature: the job demand-control-support model and the effort-reward imbalance model. In both models, standardized questionnaires have been developed and frequently used to assess job stress. Unemployment has also been reported to be associated with increased mortality and morbidity, such as by cardiovascular disease, stroke, and suicide. During the past two decades, a trend toward more flexible labor markets has emerged in the private and public sectors of developed countries, and temporary employment arrangements have increased. Temporary workers often complain that they are more productive but receive less compensation than permanent workers. A significant body of research reveals that temporary workers have reported chronic work-related stress for years. The Japanese government has urged all employers to implement four approaches to comprehensive mind/body health care for stress management in the workplace: focusing on individuals, utilizing supervisory lines, enlisting company health care staff, and referring to medical resources outside the company. Good communications between occupational health practitioners and physicians in charge in hospitals/clinics help employees with psychosomatic distress to return to work, and it is critical for psychosomatic practitioners and researchers to understand the basic ideas of work-related stress from the viewpoint of occupational health.

Clinical application of somatosensory amplification in psychosomatic medicine

Many patients with somatoform disorders are frequently encountered in psychosomatic clinics as well as in primary care clinics. To assess such patients objectively, the concept of somatosensory amplification may be useful. Somatosensory amplification refers to the tendency to experience a somatic sensation as intense, noxious, and disturbing. It may have a role in a variety of medical conditions characterized by somatic symptoms that are disproportionate to demonstrable organ pathology. It may also explain some of the variability in somatic symptomatology found among different patients with the same serious medical disorder. It has been assessed with a self-report questionnaire, the Somatosensory Amplification Scale. This instrument was developed in a clinical setting in the U.S., and the reliability and validity of the Japanese and Turkish versions have been confirmed as well.Many studies have attempted to clarify the specific role of somatosensory amplification as a pathogenic mechanism in somatization. It has been reported that somatosensory amplification does not correlate with heightened sensitivity to bodily sensations and that emotional reactivity exerts its influence on somatization via a negatively biased reporting style. According to our recent electroencephalographic study, somatosensory amplification appears to reflect some aspects of long-latency cognitive processing rather than short-latency interoceptive sensitivity.The concept of somatosensory amplification can be useful as an indicator of somatization in the therapy of a broad range of disorders, from impaired self-awareness to various psychiatric disorders. It also provides useful information for choosing appropriate pharmacological or psychological therapy. While somatosensory amplification has a role in the presentation of somatic symptoms, it is closely associated with other factors, namely, anxiety, depression, and alexithymia that may also influence the same. The specific role of somatosensory amplification with regard to both neurological and psychological function should be clarified in future studies. In this paper, we will explain the concept of amplification and describe its role in psychosomatic illness.

Somatization and Symptom Reduction Through a Behavioral Medicine Intervention in a Mind/Body Medicine Clinic

Abstract The authors assessed data from 1,148 outpatients in a 10-week medical symptom reduction program to determine the effectiveness of a behavioral medicine intervention among somatizing patients. The program included instruction in the relaxation response, cognitive restructuring, nutrition, and exercise. Before and after the intervention, the patients were evaluated on the Symptom Checklist-90 Revised (SCL-90R), the Medical Symptom Checklist, and the Stress Perception Scale. They were divided into high- and low-somatizing groups on the basis of the pretreatment SCL-90R somatization scale. At the end of the program, physical and psychological symptoms on the Medical Symptom Checklist and the SCL-90R were significantly reduced in both groups, with the reductions greater in the high-somatizing group. Improvements in stress perception were about the same in both groups, but the absence of an untreated control group precluded estimates of how much the improvements resulted from the behavioral medicine intervention and how much from natural healing over time.

Association of metabolic syndrome with depression and anxiety in Japanese men

AIM The evidence is conflicting as to whether or not metabolic syndrome (MetS) is associated with depression and anxiety. For this reason, we have investigated the association of MetS with depression and anxiety in Japanese men. METHODS MetS was defined as in the new (2006) criteria of the International Diabetes Federation (IDF), and depression and anxiety were assessed using the Profile of mood states (POMS), in 1215 male Japanese workers. The relationship between MetS and these mental conditions was assessed by logistic-regression analysis after controlling for age, gender, obesity, medical history (cardiovascular disease and diabetes), lifestyle habits (smoking, alcohol consumption, exercise and sleep) and work situation. Trend analyses for a positive association between MetS components and depression and anxiety were also performed. RESULTS A total of 148 (12.2%), 92 (7.6%) and 170 (14.0%) patients were diagnosed with MetS, depression and anxiety, respectively. MetS was significantly related to depression, and waist circumference contributed significantly to the relationship. Trend analysis of the number of positive MetS components and depression showed a positive trend that was of borderline significance (P(trend)=0.06). No relationship was found between MetS and anxiety. Trend analysis of the number of positive MetS components and anxiety failed to show a clear trend (P(trend)=0.57). CONCLUSION A positive relationship was found between MetS and depression, but not between MetS and anxiety, in male Japanese workers. The specific factors comprising MetS, such as waist circumference, may be a reflection of the depression.

Changes in body mass index by birth cohort in Japanese adults: results from the National Nutrition Survey of Japan 1956–2005

Background The National Nutrition Survey, Japan (NNS-J) provides annual anthropometric information for a whole nation over 50 years. Based on this survey, the mean body mass index (BMI) of Japanese men and elderly women has increased in recent decades, but that of young women has decreased. We examined the effect of birth cohort on this phenomenon. Methods We analysed data from the NNS-J for subjects aged 20–69 years. BMI during 1956–2005 and the prevalence of overweight and obesity (BMI ≥ 25 kg/m2) during 1976–2005 were estimated. Results The BMI increased with age in every birth cohort, with similar increments, and did not peak until 60–69 years of age. However, with cross-sectional age, the BMI usually peaked before 60–69 years of age. The differences among cohorts already existed at 20–29 years of age, and slightly increased in men between 20–29 and 30–39 years of age. The BMI in all male age groups increased from the 1891–1900 through 1971–80 cohorts. However, in women, the figure increased until the 1931–40 cohorts, but later decreased. Changes in prevalence were generally consistent with changes in BMI. The recent increase (decrease in young women) in the mean BMI is attributable to birth cohort, indicating that thinner (fatter) and less recent birth cohorts have been replaced by fatter (thinner) ones. Conclusions A cohort effect was quantitatively demonstrated based on a repeated annual survey. In Japan, the differences in BMI among cohorts were already established by young adulthood.

Association of the metabolic syndrome with depression and anxiety in Japanese men: a 1-year cohort study.

Recent studies on the association between the metabolic syndrome (MetS) and depression have reported conflicting findings. This 1‐year cohort study aims to evaluate the association of MetS with the development of both depression and anxiety.

Effects of gender and marital status on somatic symptoms of patients attending a mind/body medicine clinic.

Abstract To clarify the mechanisms of gender-related mind/body relationships, the authors analyzed the characteristics of 1,132 outpatients (848 women and 284 men) attending a mind/body medicine clinic. At entry in the program, the patients completed the Medical Symptom Checklist, Symptom Checklist-90 revised (SCL-90R), and Stress Perception Scale. Women reported 9 out of 12 symptoms (fatigue, insomnia, headache, back pain, joint or limb pain, palpitations, constipation, nausea, and dizziness) more frequently than the men did. Being a woman was a predictor of the total number of somatic symptoms endorsed. SCL-90R somatization scores were significantly higher in nonmarried women than in married women. Perceived stress ratings of family and health were higher in women than in men, despite the lower degree of perceived stress concerning work. Women, especially nonmarried women, were more likely to report somatic discomfort. Gender appears to be an important factor in relation to the report of somatic symptoms in stress-related conditions.

Reporting of somatic symptoms as a screening marker for detecting major depression in a population of Japanese white-collar workers

OBJECTIVE The objective of this study was to assess screening practices for detecting major depression in workers complaining of somatic symptoms. METHODS A total of 1443 Japanese white-collar workers (991 men and 452 women, mean age 34 years) completed a medical symptom checklist (major 12 somatic symptoms) and were diagnosed using the structured clinical interviews of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). RESULTS There were 42 cases (2.9%) with major depression in the total sample. Of the 902 subjects without somatic symptoms, only one (0.1%) was identified as having major depression. The prevalence of the disorder was positively associated (P<.001) with the total number of somatic symptoms, and the area under the receiver operator characteristic curve was 0.92 for men and 0.81 for women, which showed the sensitivity and specificity of the total number of somatic symptoms for detecting major depression. CONCLUSION The number of reported somatic symptoms is a simple and useful predictor of major depression.

Associations of insomnia with job strain, control, and support among male Japanese workers

OBJECTIVE To assess the relationship between job stress and insomnia among office workers. METHODS This cross-sectional study examined 1209 male workers (mean age 43 years) at periodic health checkups in 2007. Insomnia was defined as consistently experiencing any of three sleep disorder symptoms (i.e., difficulty initiating sleep, difficulty maintaining sleep, and early-morning awakening) in a recent two-week period. Job stress indices included job demand, control, strain (job demand/control), and social support, as measured by the Job Content Questionnaire. RESULTS The prevalence of insomnia was 4.7%. After adjusting for age, perceived daily stress, sleep dissatisfaction, lifestyle factors, and physical comorbidities, the risk of insomnia increased with a higher degree of job strain (odds ratio 2.3, 95% confidence intervals 1.3-4.0) and decreased with a higher degree of job control (0.5, 0.3-0.8). The combination of high job strain with low degree of control or social support had an approximately three times higher risk of insomnia than that of low job strain with high degree of control or support. CONCLUSIONS Both job strain and job control had an independent effect on insomnia, and the association between job strain and insomnia was mediated by the buffering effects of control and support.

Major Depression and Somatic Symptoms in a Mind/Body Medicine Clinic

This study examined the prevalence of somatic symptoms and psychiatric characteristics of major depression in a Japanese psychosomatic outpatient clinic. A total of 2,215 outpatients referred for mind/body complaints were assessed by DSM-III-R or DSM-IV. Somatic symptoms were rated using the Cornell Medical Index Questionnaire. Ninety-one outpatients (4.1%) were diagnosed with major depression. Prevalence of fatigue (86%), insomnia (79%), nausea/vomiting (50%), and back pain (36%) as well as degrees of psychosocial stress (DSM-III-R axis IV) were higher (all p < 0.05) and scores of global assessment of psychosocial functioning (DSM-III-R/DSM-IV axis V) were lower (p < 0.001) in the major depressive patients compared to the remaining outpatients. Among the major depressive patients, the total number of somatic symptoms was larger (p < 0.05) in patients with ‘severe’ major depressive episodes than in those with ‘mild’ depressive episodes. These findings suggest that the level of depression is closely linked to the reporting of somatic symptoms in a psychosomatic medicine population.