Probiotics Lower Rehospitalization Rates in Bipolar Disorder

By Chris Aiken, MD: For More Info, Go Here…

The first clinical trial of probiotics in bipolar disorder is out, and the results look promising. Probiotics lowered the rate of rehospitalization after a manic episode, according to a small controlled trial released this month.1 This marks the first clinical trial of probiotics in bipolar disorder, and it builds on previous research that has found promise for these “healthy bacteria” in depression, anxiety, cognition, and autism.2–5

Led by Dr Faith Dickerson at Sheppard Pratt Health System, the researchers randomized 66 patients to receive either a probiotic capsule or placebo for 6 months along with their usual medications after a hospital stay for mania. During that time, 50% of the patients required rehospitalization, but the rate was lower—by a factor of 3—in the probiotic group. A similar reduction was seen in the duration of hospital stays for patients who were given the probiotic.

Mind-gut mechanisms

The idea that the gut flora can influence mental illness dates to the early 20th century.6 Bench research has since clarified some of the specifics behind this “mind-gut connection.” Inflammation worsens mood disorders, and the microbial flora can alter inflammatory processes through effects on the immune system. The current study upheld that hypothesis—the degree of improvement correlated with baseline markers of inflammation.1 Other potential mechanisms for probiotics include effects on neuroplasticity (through brain-derived neurotrophic factor), neurotransmitters (increases in serotonin, GABA, N-acetyl aspartate, and glutamate), and regulation of stress hormones along the HPA Axis.2,3,7

The right strain

The gut flora can have positive or negative effects on health depending on which strains are dominant. This study used 2 strains that are thought to have beneficial effects on immune function—Bifidobacterium lactis bb-12 and Lactobacillus rhamnosus GG (or LGG). These strains are found in breast milk and have a strong safety record in humans [Dickerson F. Personal Communication, April 27, 2018].

Other studies in depression and anxiety used different strains from the Bifidobacterium and Lactobacillus families, but they involved milder symptoms and may not translate to bipolar mania (Table). There are risks in deviating too far from the exact strains used in a study, as seemingly minor differences can affect outcomes. For example, the 299v strain of Lactobacillus plantarum improved irritable bowel syndrome (IBS) in several studies, but IBS worsened with the MF1298 strain of the same organism.8–10 In terms of mental health, there are no clear examples of worsening psychiatric symptoms with probiotics, although one strain failed to help older adults (Lactobacillus reuteri) despite alleviating colic in infants.2

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