As we have reported many times here at Optimist Daily, our gut microbiome is extremely influential in how our body operates. We’ve previously reported on the possible role this group of bacteria plays in medical conditions such as anxiety, strokes, and overeating.

Now, a new study from the University of Basel and the University Psychiatric Clinics Basel (UPK) has revealed they also play a role in depression. The team found that probiotics can support and enhance the effectiveness of antidepressants, possibly shining a light on how we can improve treatment for the disease and use our guts to our advantage.

How do the gut and depression interact?

Through previous research, a clear connection between the gut microbiome and depression has been acknowledged. One study concluded that patients with depression have a higher than average chance of intestinal and digestive problems. Another showed that when mice were implanted with gut bacteria from patients with depression they developed depression-like behavior, such as decreased interest in their surroundings.

The breakthrough study looked at the impact of adding probiotics to the diet of patients taking antidepressants. 21 of the participants were given the supplement and 26 were given the placebo for 31 days on top of their usual medication. Testing at the end of this period, and then four weeks later, revealed a greater improvement of symptoms in the probiotic-taking participants than in the placebo group.

In addition, the makeup of the microbiome in the patients who took probiotics changed. Here, stool samples revealed an increase in lactic acid bacteria at the end of treatment, though decreased again after four weeks of not taking the supplement. “It may be that four weeks of treatment is not long enough and that it takes longer for the new composition of the intestinal flora to stabilize,” explains Anna-Chiara Schaub, one of the lead authors of the study.

The future is probiotic

Complex interactions are going on here between the microbiome and the brain, with intricate messaging between the two being the culprit behind the results of the study. It’s clear that the presence and population of certain bacteria play a role in depression, however, more research is needed before we can say exactly what is going on here.

“With additional knowledge of the specific effect of certain bacteria, it may be possible to optimize the selection of bacteria and to use the best mix in order to support treatment for depression,” adds Schaub.

The team emphasizes that this bacteria-enhancing supplement is not suitable as a sole treatment option, though it could allow humans to manage depression more successfully.

Source study: Translational Psychiatry – Clinical, gut microbial and neural effects of a probiotic add-on therapy in depressed patients: A randomized controlled trial