Background: Mental disorders affect about one-third of the human population, are typically chronic and significantly decrease the quality of life. Presently, the treatment of mental illnesses is far from adequate with a substantial proportion of the patients being pharmacoresistant and suffering from relapses. One of the reasons for this complicated situation is that we do not precisely know about the causes of mental disorders, so their treatment cannot be causal. The etiology of a mental disorder is typically based on a combination of molecular (genetic) and environmental factors. Aim: The aim of the project is to discover the gene-environment interactions (GxE) in a wide spectrum of mental disorders. Methods: The design of our study is innovative in the sense that we intend to study large groups of associated mental disorders as a whole instead of in isolation. This would enable us to map out the possible environmental causal factors in detail in relation to their character, magnitude and timing. The project also allows a study of genetics (including epigenetics and microbiomes) as well as the environment simultaneously. We plan on involving three study groups: the first group are patients suffering from schizophrenia or a mood disorder such as major depression, recurrent depressive disorder and bipolar affective disorder; the second group of patients have anxiety disorders; and the third group are healthy volunteers from the general population who are genetically unrelated. All of the study subjects will undergo the following assessments: a psychiatric examination, the identification of stressful life events with the aid of a questionnaire, the examination of their reaction to stress, genetic and epigenetic (microRNA) assessments and the analysis of oral and gut microbiome. Conclusion: We expect that some of the genetic as well as environmental factors in the studied mental disorders are shared, while some others are specific. We also expect that the GxE (gene-environment interaction) in schizophrenic and affective disorders will be different from the GxE in anxiety disorders and that the GxE in the studied mental disorders will differ generally from the GxE in healthy volunteers. Our results can help in the prevention and individualized treatment of a range of mental disorders.

Background Both genetic and environmental factors are important in etiology of mental disorders. Calculating polyenviromic risk/protective scores provides an updated perspective in research on the environmental causes of psychiatric disorders. We aimed to compare environmental risk and protective factors in patients with psychosis or a mood disorder (PSYCH+MOOD) and those with an anxiety disorder (ANX). Methods We administered the internationally accepted questionnaire from the EUropean Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study, enriched with mood and anxiety disorder-relevant measures, to patients at two large university hospitals in the Czech Republic. Results Ninety-four PSYCH+MOOD patients (average age 42.5 years; 46 males) and 52 ANX patients (average age 47.2 years; 17 males) participated. Neither polyenviromic risk score nor polyenviromic protective score differed significantly between PSYCH+MOOD and ANX groups (p = 0.149; p = 0.466, respectively). Conclusion Scientific validity of the polyenviromic risk/protective score construct must still be demonstrated in large psychiatric samples, ideally in prospective studies. Nevertheless, researchers have already started to investigate environmental factors in the etiology of mental disorders in their complexity, similarly to polygenic risk scores.