What is "psychobiotic"

a. of, or relating to both the mind and the body

Psychobiotics are defined by Dinan et al. as those living organisms that on sufficient ingestion produces a health benefit in those patients with psychiatric, or neurological, illnesses. Research to understand the mechanisms of psychobiotics on the gut–brain axis and enteric nervous system is currently under way. Preliminary evidence suggests modulation of neuroimmunologic, neuroinflammatory, and neurohormonal pathways. Other possible mechanisms identified include modulation of the hypothalamic–pituitary–adrenal axis, the vagus nerve, microglia, myelination, and prefrontal cortex gene expression.

Additionally, research has correlated the oral microbiome to cognitive function.

Psychobiotics can also be defined as microbes that have negative neurological interactions. Recently it was shown microbes may play a role in the formation of amyloid-β.