Psychobiotics is a relatively new and emerging field of psychiatry. The body's microbiome plays important roles in inflammatory response and neurologic function.
Mania
Certain individuals with acute mania have been found to have elevated levels of inflammation, suggesting a possible role for probiotic use.
A small study demonstrated that the use of supplementation psychobiotics (Lactobacillus rhamnosus strain GG and Bifidobacterium animalis subsp. lactis strain Bb12) was associated with a lower rate of rehospitalization in patients who have been recently discharged following hospitalization for mania.[1]
The effects are hypothesized to be due to modulation of central nervous system inflammation through the gut–brain axis.