Results of analysis confirm that intestinal flora play an important role in health, including mental health.
Probiotics can support the effect of antidepressants and help alleviate depression, the results of a study from the University of Basel and the University of Psychiatric Clinics Basel (UPK) showed.
Investigators have been researching ways to improve existing therapies and develop new ones for individuals with depression. Medication and psychotherapy can help. However, symptoms persist for some individuals.
It is known from the results of previous studies that individuals with depression show an above-average prevalence of digestive and intestinal problems.
If the intestinal flora of individuals with depression is implanted in mice raised in sterile conditions, then the animals also developed depressive-like behavior, including less energy and a decreased level of interest in their surroundings compared with their peers, investigators said.
The microbiome-gut-brain axis is a promising approach.
The investigators suspected that the composition of the bacterial community in the gut plays an important role in depressive symptoms. They systemically investigated the effects of probiotics on individuals with depression.
All the individuals included in the study were inpatients at UPK and were given a probiotic or a placebo, for 21 and 26individuals, respectively, for 31 days, in addition to antidepressants. The participants nor the study staff members knew which preparation the individuals were taking throughout the study period.
Investigators carried out a series of tests on the individuals immediately before treatment, at the end of the 31 days, and again 4 weeks later.
They found that the composition of their intestinal flora changed, at least temporarily. In the probiotic group, an analysis of stool samples showed an increase in lactic acid bacteria at the end of the treatment, an effect that was accompanied by a reduction in depressive symptoms.
However, they found that the levels of these health-promoting gut bacteria decreased over the following 4 weeks.
“It may be that 4 weeks of treatment is not long enough and that it takes longer for the new composition of the intestinal flora to stabilize,” Anna-Chiara Schaub, MSc, 1 of the lead authors of the study from UPK, said in a statement.
Additionally, the investigators found that the effect of taking probiotics was seen in relation to brain activity using magnetic resonance imaging when viewing fearful or neutral faces. In individuals with depression, certain brain regions for emotional processing behave differently than in individuals who have good mental health.
After 4 weeks of probiotics, they found that the brain activity normalized in the probiotic group but not in the placebo group.
: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,” Schaub said.
The investigators think that it is important to use a wide range of bacteria in the form of probiotics. They also emphasized that probiotics are not suitable as sole treatment for depression.
'Good' bacteria to tackle depression. Science Daily. News release. June 9, 2022. Accessed June 23, 2022. https://www.sciencedaily.com/releases/2022/06/220609155718.htm