Microbiological aid in depression – wissenschaft.de

As the study shows, the gut flora also plays an important role in our mental health: By influencing the bacterial community in the gut with probiotics, the effectiveness of antidepressant therapy can be significantly improved. Patients’ mood is improved by the increased colonization of the gut with certain bacteria and it alleviates the typical side effect of depression, the researchers say. According to them, however, further research should now explore the potential of using probiotics in therapy in even more detail.

Important little creatures live in us: In recent years, science has increasingly focused on the health importance of bacteria in our digestive system. The composition of the gut flora has been shown to be associated not only with the immune system and purely physical effects, but also with neurodegenerative diseases and psychological problems. Some of the characteristics of the human microbiome are associated with the development of depression and anxiety, for example. It is said that some gut bacteria can affect the nervous system through their waste products. This so-called gut-brain axis has now developed into an important area of ​​research.

Additional probiotic therapy

The researchers, led by Anna-Chiara Schaub from the University of Basel, are looking specifically at the extent to which the use of probiotics as part of the pharmacological treatment of depression can have a beneficial effect. They explain that there is a need to find ways to improve existing therapies and develop new ones. While antidepressants can often lighten the gloomy mood of those affected, in many cases the effect leaves something to be desired and lacks a decisive kick to stabilize quality of life in the long run.

A total of 47 volunteers who were admitted to psychiatric hospitals due to depression took part in the study. Before starting therapy, scientists recorded patients’ depressed state with standard tests, and their brain responses to specific stimuli were also recorded using functional magnetic resonance imaging (fMRI). Then, therapy began, in which half of the respondents took the probiotic in addition to standard antidepressants for 31 days. It was a commercially available formulation containing eight different strains of lactic acid bacteria believed to have beneficial effects. On the other hand, the control group unknowingly received a dummy preparation (placebo) without bacteria. To accompany the experiment, the researchers subjected all study participants to a series of tests.

mood-boosting effect

The results showed that antidepressants substantially reduced symptoms of depression in all subjects. The researchers found, however, that in the probiotic group, the mood of the study participants improved significantly more than in the placebo group. The effect was also accompanied by a change in the intestinal flora: in the probiotic group, studies of stool samples confirmed an increase in the number of lactic acid bacteria in the composition of the intestinal microbial community. However, after the probiotics were stopped, the proportion of these microbes dropped significantly over the next four weeks, the researchers found. “Perhaps four weeks of treatment is not enough and the new gut flora composition takes longer to stabilize,” says Schaub.

Another effect of taking probiotics was an effect on brain activity, the team reported. It is known that some areas of the brain responsible for emotional processing react differently in patients with depression than in mentally healthy people. This is also reflected in certain patterns when looking at the neutral and scared faces that scientists recorded with fMRI. According to the study, adequate brain function normalized in people in the probiotic group. However, scientists were unable to determine this effect in the placebo group.

The results now show the potential of using probiotics to treat mental health problems, the researchers say. According to them, they are not suitable as the only therapy in the clinical treatment of depression, but the additional effect may be important. However, more research is needed, emphasizes Schaub: “The microbiome-gut-brain axis has been under investigation for several years, but the exact mechanisms are still only partially clear. With additional knowledge about the specifics of the action of certain bacteria, the selection of bacteria could be optimized and the best blend to support the treatment of depression could be used, the researcher says.

Source: University of Basel, specialist article: Translational Psychiatry, doi: 10.1038 / s41398-022-01977-z

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