BackgroundInteroception refers to the multisensory integration and perception of the body’s internal state within the central nervous system, which involves learning, memory, emotions, and experiences. Interoceptive dysfunction has been associated with alexithymia and alexisomia. Despite growing academic interest in interoception, standardized evaluation methods have yet to be established. The widely used Heartbeat Counting Task (HCT), a representative method for assessing interoceptive accuracy, has limitations owing to the potential influence of knowledge of heart rate, time perception, and tactile sensations. Therefore, more reliable assessment methods are needed. This study focused on the feasibility of the heaviness perception test as a method for assessing interoceptive accuracy and investigates its relationship with other interoceptive indices.MethodsA total of 41 healthy volunteers (19 female; mean age 19.1 ± 0.8 years) participated in the study. The heaviness perception test was conducted using an approach similar to the method of adjustment applied to psychophysical measurements, and the absolute error scores were calculated. Other interoceptive indices investigated in this study include the HCT, Body Perception Questionnaire-Body Awareness Very Short Form (BPQ-VSF), the 20-item Toronto Alexithymia Scale (TAS-20), and Shitsu-Taikan-Sho-Scale (STSS) for alexisomia.ResultsInteroception accuracy assessed using the heaviness perception test showed a significant positive correlation with the BPQ-VSF score (r = .504, p < .01) and a negative correlation with the TAS-20 and STSS scores (TAS-20: r = –.342, p < .05; STSS: r = –.353, p < .05). However, there was no correlation between the heaviness perception test score and the absolute error score on the HCT.ConclusionsThe results suggest that the heaviness perception test is a feasible and useful method for assessing interoceptive accuracy and that it may be useful as an evaluation tool.

BackgroundHwabyung is a psychiatric syndrome originally described in Korea that presents as chronic psychosomatic distress with emotional dysregulation and heightened somatic arousal. However, no objective analysis to clarify its progressive mechanism within a universal biopsychological framework has as yet been done that incorporates insights from traditional East Asian medical psychology.MethodsWe recruited 118 patients with Hwabyung and assessed their psychological and somatic symptoms using the Hwabyung Test (HB). Levels of depression, anxiety, and anger expression, as well as biopsychological features were evaluated with the Sasang Personality Questionnaire (SPQ). Psychological and somatic symptoms of Hwabyung were predicted through a regression analysis that used three SPQ subscales: behavioral activation (SPQ-B), cognitive flexibility (SPQ-C), and emotional responsiveness (SPQ-E). Hwabyung subgroups were identified by K-means analysis and their psychosomatic and biopsychological patterns were analyzed with HB and SPQ through ANCOVA and Profile Analysis to explore underlying biopsychological dimensions beyond culture-specific frameworks.ResultsThe SPQ subscales explained 26.0% of the psychological and 14.3% of the somatic symptoms of Hwabyung. Three distinct Hwabyung subgroups (mild, moderate, and severe) were identified based on the severity of psychological and somatic symptoms. Patients with severe symptoms showed a unique SPQ subscale profile with high SPQ-B, low SPQ-C, and low SPQ-E scores, reflecting volatile, aggressive, rigid, pessimistic, repressed, and isolated biopsychological characteristics.DiscussionThis study suggests a representative SPQ subscale profile of Hwabyung and underlying mind-body interaction mechanisms within East-Asian biopsychological theory. It offers a more comprehensive and generalizable understanding of Hwabyung and other culture-bound psychosomatic syndromes, supporting improved diagnostic and intervention strategies across populations.

BackgroundPrimary prevention of depressive symptoms among independent older adults is a critical public health challenge. Lifestyle factors and social support networks are increasingly recognized as pivotal determinants of mental health in this population. However, few longitudinal studies have examined these relationships, and little attention has been directed to gender-based differences. We investigated the associations between lifestyle factors and social support networks and the depressive symptoms of community-dwelling independent older adults in a sex-stratified 3-year longitudinal study.MethodsThis study used data from the Japan Gerontological Evaluation Study. Participants were functionally independent individuals aged 65 years and older. Our final analysis included data for 6,929 individuals collected between 2019 and 2022. A logistic regression analysis was conducted with depressive symptoms in 2022 as the dependent variable. Lifestyle factors and social support networks were treated as independent variables, with age, chronic diseases, and household income included as covariates. The effects of interactions between lifestyle factors and social support networks on depressive symptoms were also analyzed.ResultsThe prevalence of depressive symptoms was 10.7% in men and 11.6% in women in the 3-year follow-up. The incidence rate of newly developed depressive symptoms (per 1,000 person-years) was 35.6 for men and 38.8 for women. Sex-based differences were found in lifestyle and social support network factors associated with depressive symptoms. In men, walking for more than 30 min per day, insomnia, and emotional support were significantly associated with the risk for depressive symptoms. In women, walking for more than 30 min per day, insomnia, and instrumental support were significantly associated with the risk for depressive symptoms. No interaction effects between lifestyle factors and social support networks on depressive symptoms were observed in either men or women.ConclusionThese findings underscore the importance of preventing depressive symptoms among older adults, particularly through the lens of gender-specific differences in lifestyle factors and social support networks associated with depressive symptoms. This study highlights the potential for developing targeted and effective primary prevention strategies by identifying modifiable determinants of depressive symptoms.

BackgroundAlthough seated isometric yoga has been shown to reduce the fatigue and pain of patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), some patients who are for the most part bedridden have difficulty practicing it. Many patients with this disease also suffer from fibromyalgia (FM). We developed a recumbent isometric yoga program for patients who were for the most part bedridden, including patients with comorbid FM. The aim of this study was to investigate the effect of this recumbent isometric yoga intervention with such patients.MethodsThis was a randomized, controlled trial of 48 adult patients (7 male, 41 female, age 20–70 years) with ME/CFS without satisfactory improvement after ≥ 3 months of conventional therapy. They were divided randomly into a yoga group (n = 24) and a control group (n = 24). The yoga group received conventional therapy with recumbent isometric yoga practice for ~ 12 weeks (25-min sessions with a yoga instructor at hospital visits and daily in-home sessions). The control group received conventional therapy alone. The effect of recumbent isometric yoga on the level of functioning was assessed by measuring Performance Status (PS). Fatigue was assessed with self-rated questionnaires, including the Chalder Fatigue Scale (FS) and Profile of Mood States (POMS). Adverse events and benefits were recorded for the yoga group.ResultsAfter the intervention period, the PS score of the yoga group was significantly lower than that of the control group (P < 0.001), suggesting an improvement in functioning level. The Chalder FS score decreased in both groups, but the decrease was greater in the yoga group than in the control group (P < 0.01). Subgroup analysis showed that the Chalder FS score was reduced significantly only in the yoga group in patients with severe disease (P < 0.001) and those with comorbid FM (P < 0.01), although the PS scores did not differ significantly. In the yoga group, a single practice session with a yoga instructor significantly reduced fatigue and increased vigor in patients with severe disease and patients with comorbid FM. Patients reported no serious adverse effects and many benefits of recumbent isometric yoga, including improvements in physical symptoms and brain fog, enhanced awareness of their limits to activities that cause post-exertional malaise, and promotion of behavioral changes to live better within their limits.ConclusionsRecumbent isometric yoga is an effective adjunctive therapy for patients with ME/CFS, including those for the most part bedridden and those who have FM.Trial registrationUniversity Hospital Medical Information Network (UMIN CTR) UMIN000023472 (Registered Aug. 4, 2016) and UMIN000030051 (Registered Nov. 20, 2017).

ObjectiveScreening tools such as the Patient Healthcare Questionnaire (PHQ) and Hospital Anxiety and Depression Scale (HADS) are useful for detecting poststroke depression (PSD). However, validation of these tools has yet to be conducted in the Singapore stroke population.MethodA total of 138 adults were administered the HADS and both two- and nine-item versions of the PHQ. Receiver operating characteristic (ROC) analyses were utilized to validate these scales against the gold standard diagnosis of PSD through the Structured Clinical Interview for DSM-IV (SCID-IV).ResultsAll the tools examined in this study had good convergent validity (rs = 0.55–0.89) and discriminative power (Area Under Curve: 0.849–0.887). The optimal cut-off scores were ≥ 7 for the HADS depression and anxiety subscales, ≥ 10 for the total score, ≥ 2 for the PHQ-2 and ≥ 8 for the PHQ-9. Additional analyses suggest that the use of both the PHQ and the HADS in specific combinations further improved diagnostic performance.ConclusionBoth the PHQ and the HADS are acceptable tools for screening for poststroke depression in Singaporean inpatient rehabilitation care settings. Furthermore, our findings lead us to recommend using PHQ-9 with HADS-A for superior screening performance at sensitivity = 83.33%, specificity = 88.33%, positive predictive value = 51.72%, and negative predictive value = 97.25%.

BackgroundIn Japan, approximately 20% of young women are underweight, a rate higher than that of other developed countries. For women, being underweight at a young age has been associated with amenorrhea, eating disorders, osteoporosis, and adverse pregnancy outcomes. We investigated young women’s knowledge of these risks and associated factors.MethodsA web-based survey was conducted among 984 Japanese women aged 18–29 years. The survey included questions about actual body weight, perceived healthy weight, body image, eating disorder tendency, knowledge of various risks and factors associated with being underweight, and sources of this knowledge. Participants were divided into underweight (< 18.5 kg/m2), normal weight (18.5–25 kg/m2), and obese (≥ 25 kg/m2) groups based on their body mass index (BMI). The body image and knowledge of health risks associated with being underweight were compared across the three groups and with women with and without an eating disorder tendency.ResultsAmong the participants, 31.5% were underweight (BMI < 18.5 kg/m2). Of these, 87.4% considered their subjective ideal weight to be underweight, and 66.1% viewed their subjective healthy weight similarly. Underweight women reported greater body satisfaction than did those in other body shape groups. While 73.2% recognized amenorrhea as a risk of being underweight, only approximately half identified infertility, eating disorders, and osteoporosis as risks and associated factors, and few were aware of adverse pregnancy outcomes. Knowledge levels did not differ between underweight and normal-weight women. Conversely, women with a tendency toward an eating disorder were more aware of the risks of osteoporosis (58.6% vs. 49.0%) and eating disorders (66.8% vs. 55.2%) than were women without a tendency toward an eating disorder.ConclusionsYoung Japanese women had insufficient knowledge about the adverse pregnancy outcomes associated with being underweight. Underweight women are not less aware of the health risks and associated factors associated with underweight than normal-weight women. The body shape of young women may not be influenced by their knowledge of health issues associated with being underweight.

BackgroundOur previous studies demonstrated that the regular practice of recumbent isometric yoga reduced the fatigue of patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Some patients with ME/CFS have postural orthostatic tachycardia syndrome (POTS); however, the effects of recumbent isometric yoga on orthostatic cardiovascular responses and whether recumbent isometric yoga improves POTS remain unknown. This pilot study was done to investigate the effect of recumbent isometric yoga on the orthostatic cardiovascular response of patients with ME/CFS.Main bodyTen adult female patients with ME/CFS performed recumbent isometric yoga for 12 weeks. Changes in their systolic blood pressure (SBP), diastolic blood pressure (DBP), and the pulse rate (PR) during an active standing test were compared before and after the 12-week regimen. Among the 10 patients, 8 manifested a normal orthostatic response and 2 manifested POTS before the yoga intervention. Patients who manifested a normal orthostatic response before yoga also manifested the normal orthostatic pattern after the yoga intervention. In contrast, the two patients who manifested POTS before the regimen showed a normal orthostatic response after completing the yoga intervention.ConclusionsThis study found that the patients who manifested POTS and performed recumbent isometric yoga for 12 weeks had a reduced increase in PR after standing up. This pilot study suggests that recumbent isometric yoga would be useful as an adjunctive nonpharmacological intervention for improving POTS in patients with ME/CFS. This finding should be confirmed in a larger number of cases.

Obesity is a chronic disease influenced by genetic, cultural, environmental, and psychosocial factors, making it difficult to manage through individual effort alone. Despite this complexity, obesity is often attributed to a lack of willpower and poor control over eating behaviors, contributing to stigma. However, research on this issue remains limited. This study quantified the extent to which multidimensional eating behaviors statistically explained the association between obesity and grit, which shared characteristics with self-control. We conducted a cross-sectional study involving Japanese adults across a wide range of age groups. Grit was measured using the 8-item Short Grit Scale. Multidimensional eating behaviors were measured using the Japanese version of the 21-item Three-Factor Eating Questionnaire-R21, including uncontrolled eating, emotional eating, and cognitive restraint. Obesity was defined as a body mass index ≥ 25.0kg/m2. A series of logistic regression models were created to analyze the association between grit and obesity with and without eating behaviors. Mediation analyses using the Karlson-Holm-Breen method were performed. Of the 1,641 adults, 26.8% had obesity. Higher grit level was associated with a lower likelihood of obesity, less uncontrolled and emotional eating, and higher cognitive restraint. Grit was positively associated with cognitive restraint and negatively associated with uncontrolled and emotional eating; these multidimensional eating behaviors statistically accounted for the association between grit and obesity. Uncontrolled and emotional eating fully accounted for the association, whereas cognitive restraint partially accounted for it. These findings are consistent with the possibility of mediation through eating behavior in the relation between grit and obesity. Our findings suggest that healthcare providers and policymakers should prioritize addressing multidimensional eating behaviors that explain the link between grit and obesity rather than on grit itself. Identifying and managing impairments in eating behavior rather than attributing obesity to an individual's lack of willpower may help reduce stigma and support effective obesity prevention strategies.