Here, we define a psychobiotic as a live organism that, when ingested in adequate amounts,
produces a health benefit in patients suffering from psychiatric illness. As a class of probiotic,
these bacteria are capable of producing and delivering neuroactive substances such as
gamma-aminobutyric acid and serotonin, which act on the brain-gut axis. Preclinical
evaluation in rodents suggests that certain psychobiotics possess antidepressant or
anxiolytic activity. Effects may be mediated via the vagus nerve, spinal cord, or …