Short-chain fatty acids in mood and schizophrenia spectrum disorders: Evidence in the field and translational perspectives

The etiology of mood and schizophrenia spectrum disorders remains largely unknown. In recent years, several studies have focused on the role of the microbiome-gut-brain-axis (MGBA) in its etiology, providing several novel insights. The communication within MGBA involves various pathways leading through the vagus nerve and the bloodstream mediators. The latter are represented by short-chain fatty acids (SCFAs), produced by gut microbiota from dietary fiber. To date, several physiological and pathophysiological roles in the periphery and the central nervous system for SCFAs have been suggested. Studies investigating gut microbiota have consistently reported a decreased abundance of bacteria-producing SCFAs in people with mood and schizophrenia spectrum disorders. Yet, studies investigating faecal and blood levels of SCFAs have provided mixed findings. The present article provides a narrative review of studies examining the physiological roles of SCFAs, along with animal model and human studies addressing the involvement of SCFAs in mood and schizophrenia spectrum disorders, formulates future directions and provides translational perspectives.