Grzybowska, D. et al. 2026. The role of the gut–brain axis in the pathogenesis of depression and anxiety disorders: The significance of microbiota, bacterial metabolites, and vagus nerve signalling — A systematic review. Quality in Sport. 65, (Aug. 2026), 73951. DOI:https://doi.org/10.12775/QS.2026.65.73951.