Popular Rationalism SYN (Science You Need): Probiotics Adjuvantive Therapy Alleviates Symptoms of Major Depressive Disorder

A four-week randomized trial found probiotics reduced symptoms of major depressive disorder compared to a placebo group.

1. A four-week probiotic therapy for depressed patients aimed to assess whether the use of probiotics in the treatment of major depressive disorder (MDD) was effective at alleviating symptoms.

2. The study was a double-blinded randomized-controlled trial, consisting of a probiotic therapy for depressed patients, as well as a placebo group.

3. Outcomes were measured via a depression rating scale based on symptoms, as well as microbiome profiling and neuroimaging of the gut-brain-axis.

4. Probiotics were found to maintain microbial diversity and increased the abundance of the genus Lactobacillus. This was associated with decreased depressive symptoms in the probiotic group.

5. This research highlights the relationship between the human gut and brain, particularly in MDD, and emphasizes that probiotic treatment may be a safer and more effective therapy for MDD.

6. This is the first study of its kind to investigate whether probiotics can help relieve symptoms of depression, by looking at changes in the gut microbiota and brain.

7. The study found that after 31 days, compared to those who took a placebo, those who took a probiotic supplement experienced reduced depressive symptoms

8. Finally, putamen activation (in response to neutral faces) was significantly decreased after taking probiotics for 31 days.

Study: Clinical, gut microbial and neural effects of a probiotic add-on therapy in depressed patients: a randomized controlled trial. https://www.nature.com/articles/s41398-022-01977-z

Abstract

A promising new treatment approach for major depressive disorder (MDD) targets the microbiota-gut-brain (MGB) axis, which is linked to physiological and behavioral functions affected in MDD. This is the first randomized controlled trial to determine whether short-term, high-dose probiotic supplementation reduces depressive symptoms along with gut microbial and neural changes in depressed patients. Patients with current depressive episodes took either a multi-strain probiotic supplement or placebo over 31 days additionally to treatment-as-usual. Assessments took place before, immediately after and again four weeks after the intervention. The Hamilton Depression Rating Sale (HAM-D) was assessed as primary outcome. Quantitative microbiome profiling and neuroimaging was used to detect changes along the MGB axis. In the sample that completed the intervention (probiotics N = 21, placebo N = 26), HAM-D scores decreased over time and interactions between time and group indicated a stronger decrease in the probiotics relative to the placebo group. Probiotics maintained microbial diversity and increased the abundance of the genus Lactobacillus, indicating the effectivity of the probiotics to increase specific taxa. The increase of the Lactobacillus was associated with decreased depressive symptoms in the probiotics group. Finally, putamen activation in response to neutral faces was significantly decreased after the probiotic intervention. Our data imply that an add-on probiotic treatment ameliorates depressive symptoms (HAM-D) along with changes in the gut microbiota and brain, which highlights the role of the MGB axis in MDD and emphasizes the potential of microbiota-related treatment approaches as accessible, pragmatic, and non-stigmatizing therapies in MDD.