Toward a Deeper Understanding of Gut Microbiome in Depression: The Promise of Clinical Applicability.

The emergence of the coronavirus disease 2019 pandemic has dramatically increased the global prevalence of depression. Unfortunately, antidepressant drugs benefit only a small minority of patients. Thus, there is an urgent need to develop new interventions. Accumulating evidence supports a causal relationship between gut microbiota dysbiosis and depression. To advance microbiota-based diagnostics and therapeutics of depression, a comprehensive overview of microbial alterations in depression is presented to identify effector microbial biomarkers. This procedure generated 215 bacterial taxa from humans and 312 from animal models. Compared to controls, depression shows significant differences in ß-diversity, but no changes in microbial richness and diversity. Additionally, species-specific microbial changes are identified like increased Eggerthella in humans and decreased Acetatifactor in rodent models. Moreover, a disrupted microbiome balance and functional changes, characterized by an enrichment of pro-inflammatory bacteria (e.g., Desulfovibrio and Escherichia/Shigella) and depletion of anti-inflammatory butyrate-producing bacteria (e.g., Bifidobacterium and Faecalibacterium) are consistently shared across species. Confounding effects of geographical region, depression type, and intestinal segments are also investigated. Ultimately, a total of 178 species and subspecies probiotics are identified to alleviate the depressive phenotypes. Current findings provide a foundation for developing microbiota-based diagnostics and therapeutics and advancing microbiota-oriented precision medicine for depression.

The Impact of the COVID-19 Pandemic and Associated Control Measures on the Mental Health of the General Population : A Systematic Review and Dose-Response Meta-analysis.

BACKGROUND: To what extent the COVID-19 pandemic and its containment measures influenced mental health in the general population is still unclear. PURPOSE: To assess the trajectory of mental health symptoms during the first year of the pandemic and examine dose-response relations with characteristics of the pandemic and its containment. DATA SOURCES: Relevant articles were identified from the living evidence database of the COVID-19 Open Access Project, which indexes COVID-19-related publications from MEDLINE via PubMed, Embase via Ovid, and PsycInfo. Preprint publications were not considered. STUDY SELECTION: Longitudinal studies that reported data on the general population's mental health using validated scales and that were published before 31 March 2021 were eligible. DATA EXTRACTION: An international crowd of 109 trained reviewers screened references and extracted study characteristics, participant characteristics, and symptom scores at each timepoint. Data were also included for the following country-specific variables: days since the first case of SARS-CoV-2 infection, the stringency of governmental containment measures, and the cumulative numbers of cases and deaths. DATA SYNTHESIS: In a total of 43 studies (331 628 participants), changes in symptoms of psychological distress, sleep disturbances, and mental well-being varied substantially across studies. On average, depression and anxiety symptoms worsened in the first 2 months of the pandemic (standardized mean difference at 60 days, -0.39 [95% credible interval, -0.76 to -0.03]); thereafter, the trajectories were heterogeneous. There was a linear association of worsening depression and anxiety with increasing numbers of reported cases of SARS-CoV-2 infection and increasing stringency in governmental measures. Gender, age, country, deprivation, inequalities, risk of bias, and study design did not modify these associations. LIMITATIONS: The certainty of the evidence was low because of the high risk of bias in included studies and the large amount of heterogeneity. Stringency measures and surges in cases were strongly correlated and changed over time. The observed associations should not be interpreted as causal relationships. CONCLUSION: Although an initial increase in average symptoms of depression and anxiety and an association between higher numbers of reported cases and more stringent measures were found, changes in mental health symptoms varied substantially across studies after the first 2 months of the pandemic. This suggests that different populations responded differently to the psychological stress generated by the pandemic and its containment measures. PRIMARY FUNDING SOURCE: Swiss National Science Foundation. (PROSPERO: CRD42020180049).

Mental Health Among College Students During the COVID-19 Pandemic in China: A 2-Wave Longitudinal Survey.

BACKGROUND: Growing evidence supports a clear association between COVID-19 pandemic and mental health. However, little is known about the longitudinal course of psychopathology in young adults at different stages of the pandemic. METHODS: This large-scale, longitudinal, population-based survey was conducted among college students in China. The rates of three mental health problems (acute stress, anxiety, and depressive symptoms), and their change patterns at two phases of the pandemic (early vs under-control) were measured. Predictors of changes in mental health symptoms were examined utilizing multivariate regression. RESULTS: Among the 164,101 college students who participated in the first wave survey (T1=during onset of outbreak), 68,685 (41.9%) completed a follow-up survey (T2=during remission). In the follow-up survey, the prevalence of probable acute stress (T1: 34.6%; T2: 16.4%) decreased, while the rates of depressive (T1: 21.6%; T2: 26.3%) and anxiety symptoms (T1: 11.4%; T2: 14.7%) increased. Senior students, with suspected or conformed cases in their community and COVID-19 related worries (all AORs > 1.20, ps < 0.001) were found to have a higher risk of developing mental health problems in at least one wave. Less physical exercise, low perceived social support, and a dysfunctional family were found to negatively impact psychological symptoms. CONCLUSIONS: Acute stress, anxiety, and depressive symptoms have been prevalent among college students during the COVID-19 epidemic, and showed a significant increase after the initial stage of the outbreak. Some college students, especially those with the risk factors noted above, exhibited persistent or delayed symptoms.