Major depressive disorder (MDD) is among the most prevalent mental disorders worldwide. Factors causing the pathogenesis of MDD include gut microbiota (GM), which interacts with the host through the gut–brain axis. In previous studies of GM in MDD patients, 16S rRNA sequencing was used, which provided information about composition but not about function. In our study, we analyzed whole metagenome sequencing data to assess changes in both the composition and functional profile of GM. We looked at the GM of 36 MDD patients, compared with that of 38 healthy volunteers. Comparative taxonomic analysis showed decreased abundances of Faecalibacterium prausnitzii, Roseburia hominis, and Roseburia intestinalis, and elevated abundances of Escherichia coli and Ruthenibacterium lactatiformans in the GM of MDD patients. We observed decreased levels of bacterial genes encoding key enzymes involved in the production of arginine, asparagine, glutamate, glutamine, melatonin, acetic, butyric and conjugated linoleic acids, and spermidine in MDD patients. These genes produced signature pairs with Faecalibacterium prausntizii and correlated with decreased levels of this species in the GM of MDD patients. These results show the potential impact of the identified biomarker bacteria and their metabolites on the pathogenesis of MDD, and should be confirmed in future metabolomic studies.

Background. In 2020, the COVID-19 pandemic evoked a variety of research into the virus and its effects on mentalhealth. A variety of mental health and psychological problems have been reported: stress, anxiety, depressivesymptoms, insomnia, denial, stigma, anger and fear. Objectives. To assess the level of anxiety, depression and distress in the general population during the lockdownin Russia and to reveal factors associated with distress. Methods. An online survey was carried out from 22–27 April 2020 (the fourth week of lockdown) among the generalpopulation (mostly Moscow residents). The survey questions covered general information about people’s social anddemographic characteristics, experience of COVID-19, health condition (physical and mental), attitudes and views onthe pandemic, and the need for psychological support. The survey included the Hospital Anxiety and Depression Scale(HADS) and evaluation of the preceding week’s subjective distress level using a visual numeric scale (from 0 to 10). Wealso asked respondents to specify the causes of distress, adopted from the WHO information sheet relating to themajor psychological challenges of the COVID-19 pandemic. Results. In total, 352 responses were collected (men = 74, women = 278; age (M ± SD) = 36.81 ± 11.36 y.o.).Most respondents (n = 225, 63.92%) did not have any personal experience of the coronavirus infection. Normallevels of anxiety and depression scores were prevalent in the sample. Higher than normal levels of HADS anxiety/depression ( 7 scores) were observed in 105 (29.83%) and 59 (16.76%) respondents, respectively; mean (95% CI)scores for HADS anxiety/depression were 6.23 [5.77, 6.68] /4.65 [4.22, 5.08] (women) and 4.20 [3.32, 5.09] /3.46[2.63, 4.29] (men), respectively.The leading causes of distress were: 1) the risk of financial problems in the future (n = 267, 76.3%); 2) violationof plans and the disruption to normal life (n = 235, 67.1%; and n = 240, 68.6%, respectively); 3) the health of elderlyor chronically diseased relatives (n = 205, 58.6%) and 4) being in self-isolation (n = 186, 53.1%). Conclusion. The level of anxiety and depression during the COVID-19 pandemic in the study sample did not exceed thenorm for the population in non-pandemic conditions. Our assessment of distress levels captured existing emotionalproblems, and distress levels were found to be connected with the reported need for psychological support.

Introduction The current study aimed to investigate the rates of anxiety, clinical depression, and suicidality and their changes in health professionals during the COVID-19 outbreak. Materials and methods The data came from the larger COMET-G study. The study sample includes 12,792 health professionals from 40 countries (62.40% women aged 39.76 ± 11.70; 36.81% men aged 35.91 ± 11.00 and 0.78% non-binary gender aged 35.15 ± 13.03). Distress and clinical depression were identified with the use of a previously developed cut-off and algorithm, respectively. Statistical analysis Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses, and Factorial Analysis of Variance (ANOVA) tested relations among variables. Results Clinical depression was detected in 13.16% with male doctors and ‘non-binary genders’ having the lowest rates (7.89 and 5.88% respectively) and ‘non-binary gender’ nurses and administrative staff had the highest (37.50%); distress was present in 15.19%. A significant percentage reported a deterioration in mental state, family dynamics, and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (24.64% vs. 9.62%; p < 0.0001). Suicidal tendencies were at least doubled in terms of RASS scores. Approximately one-third of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop clinical depression was associated with a history of Bipolar disorder (RR = 4.23). Conclusions The current study reported findings in health care professionals similar in magnitude and quality to those reported earlier in the general population although rates of clinical depression, suicidal tendencies, and adherence to conspiracy theories were much lower. However, the general model of factors interplay seems to be the same and this could be of practical utility since many of these factors are modifiable.

To investigate the effects of diet on the gut microbiota and to assess the relationship of these factors with depression. Microorganisms that predominate in depressed patients were identified and associations of the identified organisms with the patients' diet were performed. Fourteen depressed patients and 14 healthy volunteers with the same socio-demographic parameters were included in the study. The Hamilton Depression Scale, Generalized Anxiety Disorder Questionnaire, and the Center for Epidemiologic Studies Questionnaire were used. Erysipelatoclostridium and Clostridium innocuum species were 11.3 and 14.4 times higher in depressed patients compared with healthy controls. Fusicatenibacter saccharivorans, Faecalibacterium prausnitzii and Roseburia faecis species, as well as members of the genus Roseburia were statistically significantly more abundant in the healthy volunteers group (6.5, 2.14, 8.75 and 5.2 times more frequently compared to patients). The presence of these microorganisms was correlated with dietary components. Our study revealed groups of microorganisms that differ in healthy volunteers and depressed patients. The association of these microorganisms with the diet was shown, which partially confirmed the influence of a «healthy diet» on the development of depressive disorders.

BACKGROUND: Schizoaffective disorder (SAD) is one of the most complex and controversial diagnoses in clinical psychiatry. Despite the significant changes that have occurred in the conceptualization of SAD in modern classifications and the publications of recent years, many unresolved issues remain regarding the disease, from the point of view of clinical psychiatry and basic neuroscience. AIM: The purpose of this paper is to summarize published data on the concept of SAD, its clinical characteristics, cognitive profile, potential biomarkers, as well as the place of the disease in the following modern international classifications: the International Classification of Diseases (ICD) 9th, 10th and 11th revisions, and the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). METHODS: We undertook a review of the scientific studies in the relevant bibliographic systems and databases (eLIBRARY, PubMed) of the past 15 years. The descriptive analysis method was used to summarize the collected information. A total of 70 publications were selected for review, including different versions of international classifications of diseases (ICD and DSM-5). RESULTS: There has been some improvement in the inter-rater reliability of SAD criteria in modern classifications, but this has not yet led to a clearer understanding among mental health specialists, while the various subtypes of SAD identified so far fail to account for the heterogeneity in the clinical presentation of the disorder. The dimensional approach to diagnosing SAD, according to which the intensity of psychotic and affective symptoms can fluctuate over time and they can influence one another, more accurately reflects the disease’s ability to embody different forms. Basic research does not support the identification of a distinct cognitive, neuroimaging, or immunological SAD endophenotype that differs qualitatively from schizophrenia and affective psychoses. CONCLUSION: The conceptualization of SAD remains incomplete, and new approaches rooted in neuroscience are needed to better understand the coexistence of affective and psychotic symptoms.