Gut microbiota and treatment-resistant schizophrenia: many questions, fewer answers

The gut microbiota has a fundamental role in regulating the homeostasis of brain function and behavior. Indeed, alterations in the gut microbiota have been linked to pathological processes affecting the brain, such as those occurring in severe psychiatric disorders. Although these data can potentially reveal a wealth of information related to the underlying biological mechanisms linking psychiatric diseases to the gut microbiome, the implication for clinical guidelines and care is still unclear. This is an unsettling reality even for phenotypic manifestations of severe mental disorders associated with increased illness burden, such as treatment-resistant forms. In this editorial, we list some of the obstacles affecting gut microbiota research in psychiatry, especially with regard to treatment-resistant forms, and suggest some strategies to overcome them.