江口 哲史

Postpartum depressive symptoms (PDS) are a common mental health condition among women after delivery. Although various causative factors have been reported, PDS remains a challenging condition to predict and prevent. The disruption of the gut microbiota due to antibiotic exposure has been reported to affect psychiatric conditions. Similarly, previous research suggests that antibiotic exposure during pregnancy could be related to PDS. Therefore, this prospective study examines the association between antibiotic exposure during pregnancy and PDS for 6 months after delivery. Data were obtained from 65,272 mothers from the Japan environment and children's study, a prospective birth cohort study. The ratios of maternal PDS at 1 and 6 months after delivery were 12.3% and 10.1%, respectively. During pregnancy, 10.7% of women took antibiotics orally. Antibiotic exposure during pregnancy was associated with an increased risk of PDS only at 6 months after delivery (OR = 1.13, 95% CI [1.00, 1.26]), adjusted for potential confounding factors. An increase in Edinburgh Postnatal Depression Scale scores in relation to antibiotic exposure during pregnancy was primarily observed via psychological distress during pregnancy. Although a causal link was not established, antibiotic exposure during pregnancy may be a contributing risk factor for PDS. Therefore, when antibiotic administration is required, clinical practitioners and perinatal care providers should consider the potential risk for PDS.

Background The COVID-19 pandemic has had unprecedented impacts on mortality worldwide. This study aimed to estimate excess all-cause mortality in Japan from 2020 to 2023, stratified by age, sex and prefecture, to assess the evolving impact of the pandemic, particularly in the latter years. The study period extends beyond Japan ending the public health emergency. Methods Using national vital statistics data from 2015 to 2023, we employed a two-stage interrupted time series analysis to estimate excess mortality during the COVID-19 pandemic (2020–2023) compared with the prepandemic period (2015–2019). Models were adjusted for seasonality, long-term trends, temperature and influenza activity. We calculated excess deaths during (14 January 2020 to 7 May 2023) and after (8 May 2023 to 31 December 2023) the COVID-19 emergency. Results Japan experienced 219 516 excess deaths (95% empirical CI (eCI) 138 142 to 301 590) during the study period, corresponding to 3.7% (95% eCI 2.33 to 5.09) excess mortality. Excess mortality was negative in 2020 (−1.67%, 95% eCI −2.76 to −0.55), becoming positive in 2021 (2.19%, 95% eCI 0.9 to 3.49) and peaking in 2022 (7.55%, 95% eCI 5.96 to 9.13) before declining in 2023 (5.76%, 95% eCI 4.29 to 7.24). The <60 age group consistently showed the highest percentage excess mortality. Males had slightly higher excess mortality than females. By 2022, all prefectures exhibited positive excess mortality. The relative risk peaked in late 2022, with a smaller peak in summer 2023, coinciding with the post-emergency period. Comparing this post-emergency period with prior years shows the highest percentage excess mortality in 2022. Rural prefectures, and those with lower influenza cases, showed reduced excess mortality during the latter and post-emergency period. Conclusion Despite initial success in mitigating excess deaths, Japan saw increasing excess mortality as the pandemic progressed, with continued elevation post-emergency. The varying impact across age groups and time highlights the complex factors affecting mortality. This study’s findings underline the importance of continuous monitoring of excess mortality as a key indicator for public health dynamics.

3,4-Methylenedioxymethamphetamine (MDMA; Ecstasy) is a widely abused recreational drug that has also gained interest for potential clinical applications in mental health. With the growing recognition of gut microbiota's role in mental health, this study examined whether repeated oral MDMA administration could affect gut microbiota in the small intestine, cecum, and colon of male rats. Repeated oral MDMA administration (10 mg/kg/day for 14 days) caused significant changes in the gut microbiota across these regions, with distinct effects observed in each. PICRUSt2 analysis revealed significant alterations in several metabolic pathways in these regions, indicating potential shifts in microbial functional capabilities associated with MDMA treatment. Untargeted metabolomics analysis revealed that MDMA significantly altered levels of two metabolites-ferulic acid and methylmalonic acid-in the colon, without changes in the blood, small intestine, or cecum. Notably, methylmalonic acid levels in the colon positively correlated with Lawsonibacter and Oscillibacter. These findings suggest that repeated oral MDMA treatment can alter gut microbiota composition across intestinal regions, potentially contributing to its pharmacological effects.