Several researches clearly indicate that the gut microbiota can influence brain-derived neurotrophic factor (BDNF) levels mainly through the effect of SCFAs and this links the microbiota to neuroplasticity-related CNS systems.85 An increase in SCFAs through a fiber-rich diet was positively correlated with raising BDNF levels, which ultimately might improve ADHD symptoms.70 Our study further confirms the protective role of SCFAs in ADHD from the novel perspective of metagenomics and fecal metabolomics, which can serve as a valuable complement to the aforementioned studies. This evidence concerns the gene BDNF and attention deficit-hyperactivity disorder.