Page 38 - JCBP-3-3

Journal of Clinical and
Basic Psychosomatics Microbiota in psychosomatic disorders

by Akkasheh et al. demonstrated that probiotic symptoms and the heightened stress responses observed
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supplementation significantly reduced symptoms of in IBS, creating a vicious cycle where psychological stress
depression in patients with MDD. Patients treated with worsens gut health and vice versa. Depression and anxiety
probiotics over 8 weeks showed positive benefits on the are more prevalent among IBD patients compared to
Beck Depression Inventory, insulin levels, high-sensitivity the general population, and these mental health issues
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C-reactive protein concentrations, and glutathione levels, are often associated with disease flare-ups. A study by
further implicating the gut microbiota in mood regulation. Mikocka‑Walus et al. found that psychological stress
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Anxiety disorders have also been linked to gut microbiota was linked to increased disease activity in IBD, suggesting
imbalances. Studies such as those by Foster and Neufeld that the inflammatory processes in the gut may influence
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have shown that individuals with anxiety tend to have mood regulation. In addition, the research revealed that
lower microbial diversity and a higher abundance of depressive symptoms correlate with clinical recurrence,
pro-inflammatory bacteria, such as those belonging to and individuals experiencing depression had a markedly
the Proteobacteria phylum. These microbial shifts are reduced interval until a clinical recurrence incident
associated with increased gut permeability and systemic occurred. Dysbiosis in IBD is characterized by reductions
inflammation, which can exacerbate anxiety symptoms. in anti-inflammatory bacteria such as F. prausnitzii and an
Pre-clinical studies in animal models further support the overrepresentation of pro-inflammatory bacteria, such as
connection between the gut microbiota and anxiety-like Enterobacteriaceae. 89,90 These microbial shifts are associated
behavior. For example, microorganism-free mice, which with increased gut permeability, systemic inflammation,
are raised without any gut bacteria, exhibit exaggerated and immune dysregulation, all of which can contribute to
stress responses and increased anxiety-like behaviors, the development of both GI and psychological symptoms.
indicating that the presence of a healthy microbiota is
critical for normal stress regulation. 82 3. Therapeutic interventions targeting the
The gut–brain axis has also been implicated in the gut–brain axis
development of autism spectrum disorder (ASD), A growing body of research suggests that restoring gut
a condition characterized by social communication microbial balance through probiotics, pre-biotics, diet,
deficits and repetitive behaviors. Children with ASD and lifestyle interventions can have a significant impact on
often experience GI symptoms, and several studies have mental health. Studies have explored the use of probiotics
identified distinct gut microbiota profiles in individuals and pre-biotics to manage psychiatric conditions, such
with ASD. A study by Kang et al. found that children as depression, anxiety, and stress-related disorders, by
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with ASD had significantly lower levels of beneficial improving gut microbiota composition.
bacteria, such as Bifidobacterium and Prevotella, along Probiotics, live beneficial bacteria that improve gut
with higher levels of potentially harmful bacterial species. microbial balance, have gained attention for their role
Furthermore, multivariate studies indicated that autism- in managing mental health conditions (psychobiotics:
related alterations in overall diversity and the abundance probiotics that confer mental health benefits). Several
of specific genera were associated with the prevalence clinical studies have demonstrated the efficacy of
of autistic symptoms but not with dietary patterns. probiotics in reducing symptoms of depression and
These microbial imbalances may contribute to the GI anxiety by modulating gut microbiota and the gut–
symptoms commonly seen in ASD and may also influence brain axis. For example, a randomized controlled trial
neurodevelopmental outcomes through altered production by Kazemi et al. showed that an investigation involving
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of microbial metabolites, such as SCFAs and tryptophan 100 depressed patients who were administered probiotics
metabolites. (Lactobacillus helveticus and Bifidobacterium longum), pre-
Psychological disorders are also frequently observed biotics (galactooligosaccharides [GOS]), or a placebo over
in patients with GI diseases, such as IBS and IBD. For 8 weeks to quantify serum concentrations of tryptophan
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instance, IBS patients consistently show a high prevalence and branched-chain amino acids (measured through
of psychological comorbidities. Up to 60% of individuals high-performance liquid chromatography) significantly
with IBS also suffer from anxiety or depression, and stress is reduced depressive symptoms in patients with MDD. This
a well-established trigger for IBS symptoms, which include improvement was associated with decreased inflammatory
abdominal pain, bloating, and altered bowel habits. 85,86 markers and improved gut barrier function, suggesting
Research has shown that IBS patients tend to have altered that probiotics exert their antidepressant effects through
gut microbiota profiles, characterized by reduced microbial immune modulation and enhanced gut integrity. Probiotic
diversity and an overgrowth of pro-inflammatory species. interventions for anxiety have also been supported by
This dysbiosis is thought to contribute to both GI clinical research. In the study by Messaoudi et al.,
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Volume 3 Issue 3 (2025) 32 doi: 10.36922/JCBP025040008