The micros in our gut have important roles in inflammatory response and neurologic functioning. Because some patients with acute mania have elevated levels of inflammation, these researchers tested the effects of a probiotic combination on relapse in patients recently discharged following hospitalization for mania.

In the double-blind study, 66 patients continued their medication regimens and were randomized to receive 24 weeks of either Lactobacillus rhamnosus strain GG plus Bifidobacterium animalis subsp. lactis strain Bb12 or placebo. An inflammation score, calculated at baseline, was developed and hospitalization rates studied.

Rehospitalization rates were significantly higher with placebo than with probiotics, 51.1% vs. 24.2%. Days hospitalized also favored the probiotic group (8.3 vs. 2.8 days), as did time to first rehospitalization. Probiotic patients with higher baseline levels of inflammation had an even lower rate of first hospitalization and an approximately 90% reduction in risk for hospitalization. No serious adverse effects were reported.

This impressive study demonstrates that this probiotic combination, presumably by modulating central nervous system inflammation through the gut-brain axis, has therapeutic effects on patients with mania.

The study focused only on mania and not mixed states, hypomania, or depression.  The researchers used a specific combination of strains, obtained from a company in Denmark.  As the combination was well tolerated, there seems no reason not to try it with our patients.  In the U.S., probiotics with the specific species used in the study are available.