This study aimed to determine whether both subjective sleep quality and sleep duration are directly associated with quality of life (QOL), as well as indirectly associated with QOL through insomnia symptoms. Individuals aged 20–69 years without mental illness (n = 9305) were enrolled in this web-based cross-sectional survey. The Short Form-8 was used to assess physical and mental QOL. We used the Pittsburgh Sleep Quality Index (PSQI) and extracted items related to subjective sleep quality and sleep duration. Insomnia symptoms were also extracted from the PSQI. The hypothesized models were tested using structural equation modeling. Worse sleep quality, but not shorter sleep duration, was related to worse physical QOL. Both worse sleep quality and shorter sleep duration were related to worse mental QOL. Insomnia symptoms mediated these relationships. Subgroup analyses revealed a U-shaped relationship between sleep duration and physical/mental QOL. However, the relationship between sleep quality and physical/mental QOL was consistent regardless of sleep duration. The results suggest that subjective sleep quality has a more coherent association with QOL than subjective sleep duration. Because of its high feasibility, a questionnaire on overall sleep quality could be a useful indicator in future epidemiological studies of strategies for improving QOL.

The prevalence of circadian rhythm sleep-wake disorder (CRSWD) among patients with schizophrenia is not clear. The effect of comorbid CRSWD on such patients has also not been fully evaluated yet. Outpatients with schizophrenia in the maintenance phase who visited Tokyo Women’s Medical University Hospital between April 2018 and March 2019 participated in this study. The Brief Psychiatric Rating Scale (BPRS), the Clinical Global Impressions–Severity Illness Scale (CGI-S), Global Assessment of Functioning (GAF), World Health Organization Disability Assessment Schedule II, Insomnia Severity Index (ISI), and Morningness–Eveningness Questionnaire (MEQ) were administered, and the patient responses with and without CRSWD were compared. Of the 105 patients with schizophrenia, 19 (18.1%) had CRSWD. There were trends toward higher BPRS and lower GAF scores in the CRSWD group than in the non-CRSWD group, although these did not reach statistical significance following a false discovery rate correction. Among the BPRS subitems, the anxiety scores were significantly higher in the CRSWD group than in the non-CRSWD group (p < 0.01). CRSWD was highly prevalent among patients with schizophrenia in the maintenance phase. Comorbidities of CRSWD may affect psychopathological characteristics and psychosocial functioning.

Health anxiety (HA), defined as excessive worry about having a serious medical condition, may affect preventive behaviors during the coronavirus disease 2019 (COVID-19) pandemic. We examined the distinct role of two dimensions of HA-perceived likelihood (probability dimension) and awfulness of illness (awfulness dimension)-in self-protection, as reflected in preventive behaviors during the pandemic. Participants comprised 657 healthcare workers. Data were collected between February 24 and 26, 2021. The Short Health Anxiety Inventory determined the HA dimensions. Adherence to the government's recommendations for COVID-19 preventive behaviors was self-rated. An independent association between each HA dimension and participants' adherence to the recommendations was examined using multivariable regression. Within the analyzed sample of 560 subjects, severe HA was observed in 9.1 %. The more the participants felt awful, the less frequently they engaged in the recommended preventive behaviors (adjusted odds ratio = 0.993, 95 % confidence interval: 0.989, 0.998, p = 0.003) regardless of their profession, working position, psychological distress, sleep disturbance, and current physical diseases. However, the probability dimension was not associated with their preventive behaviors. The awfulness dimension of HA could be a more sensitive marker of preventive behaviors than the probability dimension. Paying particular attention to the awfulness dimension may help optimize self-protection strategies during the COVID-19 pandemic. A two-dimensional understanding of HA may be useful for the maintenance of the healthcare system and public health as well as healthcare workers' own health.

Evidence provides support for the therapeutic benefits of targeting avoidance in prolonged grief. However, it is not clear whether avoidance interferes with mourning through altered resilience to stress, as measured by heart rate variability (HRV). Thirty-five adults (30 female; mean age: 39.2 years), who had been bereaved for more than one year, participated in this prospective, observational study. At each of the initial assessments and up to six-month follow-ups, grief symptoms were assessed using the Complicated Grief Questionnaire, and a resting electrocardiogram was recorded to extract the high-frequency component of HRV (HF-HRV). To differentiate avoidance from grief itself, principal component analysis was used. A nonlinear cross-sectional relationship was observed between avoidance and HF-HRV (coefficient = 0.29, p = .003); the lower the avoidance, the lower the HF-HRV in the low avoidance group. Grief improved only in the low avoidance group longitudinally. The observed relationship between increased HF-HRV and decreased grief was modified by the avoidance group, such that the low-avoidance group drove this association (estimate -0.53, 95% CI -0.86, -0.21, p = .001), while the high-avoidance group did not (estimate 0.44, 95% CI -0.32, 1.20, p = .26). Despite its palliative gain, avoidance relates to the maintenance of grief longitudinally through attenuated autonomic resilience to stress.

Background/Objectives: Non-restorative sleep (NRS)—a subjective feeling of unrefreshing/insufficient rest despite adequate sleep duration—an important sleep-quality indicator is associated with depression and mortality. We examined whether insoluble dietary fiber intake is associated with NRS in Japanese adults, after adjusting for socioeconomic, lifestyle, and dietary factors. Methods: Using cross-sectional data from 5034 adult (≥20 years) respondents of the National Health and Nutrition Surveys (2014 and 2018), Japan, self-assessed NRS (coded as 1, absence as 0) was analyzed with insoluble fiber intake (g/1000 kcal) modeled as a continuous variable; logistic regression analyses with progressive adjustments included Model 1, adjusted for sex, age, and body mass index; Model 2, comprising socioeconomic and lifestyle factors; Model 3, adjusted for sleep duration; and Model 4, which included dietary energy, protein, fat, vitamin D, and magnesium. Results: Among 19.3% of participants with NRS, the median (interquartile range) insoluble dietary fiber intake was 5.45 (4.10–6.97) g/1000 kcal, with higher NRS prevalence among younger adults (<60 years), non-drinkers (no habitual alcohol consumption), and individuals with short sleep (<6 h). Higher insoluble dietary fiber intake was consistently associated with a lower NRS likelihood, before and after adjustment for potential confounders. In the fully adjusted model, younger age (<60 years), no habitual alcohol consumption, and short sleep (<6 h) were independently associated with greater odds of NRS. Conclusions: Higher insoluble dietary fiber density correlated with lower odds of NRS, indicating a significant association, rather than causation, that warrants longitudinal clarification of the temporal relationship between dietary fiber intake and perceived sleep restorativeness.