Data published in Translational Psychiatry, a Nature journal, indicated that a combination of Streptococcus, Bifidobacterium, and Lactobacillus strains called the De Simone Formulation, used in addition to customary depression treatments, decreased depressive symptom outcomes relative to the placebo, but only when the study participants complied with the protocol.
“In our study probiotic effects were only significant in a subsample with high compliance and accentuated in the follow-up after eight weeks, indicating a remission rate of 55% in the probiotics group compared to a 40% remission rate in the placebo group,” reported scientists from the University of Basel in Switzerland.
“The importance of compliance during probiotic supplementation should be highlighted and is as important as in general antidepressant therapy.”
The De Simone Formulation probiotic is distributed in North America by Rockville, Maryland-based ExeGi Pharma under the brand name, Visbiome. It is available as a medical food for the dietary management of dysbiosis associated with IBS, ulcerative colitis, pouchitis and hepatic encephalopathy. In Europe, it is sold under the name Vivomixx.
The formulation includes Streptococcus thermophilus, Bifidobacterium breve, B. longum, B. infantis, Lactobacillus acidophilus, L. plantarum, L. para-casei, and L. delbrueckii subsp. bulgaricus.
The study adds to the ever-growing area of research around the microbiota-gut-brain axis, that bi-directional interaction between the gastrointestinal tract and the nervous system. The area is gaining increasing attention from scientists and consumers.
A 2015 review in Neuropsychiatric Disease and Treatment by Linghong Zhou and Jane Foster from McMaster University in Canada noted that the bacteria present in the gut affects the communication between belly and brain, and the lack of healthy gut microbiota leads to dysfunction in the gut–brain axis, which in turn may lead to neuropsychological, metabolic, and gastrointestinal disorders.
Previous studies in humans have established certain benefits in psychiatric outcomes but many of the studies are limited by small sample sizes and certain design limitations. This new study included 47 people with current depressive episodes randomly assigned to receive 900 billion CFU/day of the probiotic combination or placebo for 21 days in addition to the usual anti-depressant treatment.
Using the Hamilton Depression Rating Sale (HAM-D) as the primary outcome, the researchers found that while both groups experienced decreases in the HAM-D scores, the probiotic group experienced greater benefits, compared to placebo.
Gut microbiota analysis also revealed that the probiotic group maintained microbial diversity and increased the abundance of the genus Lactobacillus, which itself was correlated with decreased depressive symptoms.
Additionally, brain imaging showed that neural activity in the putamen, a region involved in emotional processing and associated with depression, decreased after probiotic supplementation.
"These results are very encouraging as we seek to understand the impact of probiotics in the field of mental health," said Dr. André Schmidt, of the University of Basel and senior author of the study. "The crucial next step is to validate our findings in large-scale clinical studies and to identify biomarkers for stratified treatment guidance."
According to a release by ExeGi Pharma, the University of California San Francisco (UCSF) is planning a pilot clinical trial with the same probiotic agent in adolescents with clinical depression. That pilot trial is expected to start later this year.
Source: Translational Psychiatry
12, 227 (2022). doi: 10.1038/s41398-022-01977-z
“Clinical, gut microbial and neural effects of a probiotic add-on therapy in depressed patients: a randomized controlled trial”
Authors: A-C. Schaub et al.