Another study of fecal microbiota in a first-episode psychosis cohort found significant differences in several bacterial strains compared with a healthy control group, and those with the strongest difference had more severe psychotic symptoms and poorer response after 12 months of antipsychotic treatment.11
Autism has been linked to increased microbiota diversity, and an excess of bacteroides has been associated with a higher diversity of autism. Fecal samples from autistic children were reported to have an increase in SCFAs. Interestingly, a certain strain of lactobacillus can modulate oxytocin or reverse some autistic symptoms.
Depression has been associated with increased diversity of microbiota alpha. Patients with depression have been reported to have low numbers of bifidobacterium and lactobacillus. Certain strains have been reported to reduce depression and anxiety behaviors in animal studies. The microbiota-friendly Mediterranean diet, but not the Western diet, appears to mitigate the risk of depression. Certain probiotics have been reported to increase resilience to stress.12,13
ADHD.Some studies suggest that ADHD may be linked to factors that can alter gut microbiota, including birthing mode, type of infant feeding, maternal health, and early stressors. In addition, dietary influences on gut microbiota can modify ADHD symptoms.14
Alzheimer’s disease.Metabolic dysregulation, such as obesity and diabetes, can inflame the gut microbiota, and are known risk factors for Alzheimer’s disease.15