Page 11 - JCBP-2-4

Journal of Clinical and
Basic Psychosomatics FND and gut microbiome

brain activity in real-time, facilitating the identification of suppressing microbial pathogens, and configuring
the specific neural correlates of psychosomatic symptoms. neural networks. These effects are partly mediated by the
Besides, other kinds of psychophysiological evaluations, secretion of SCFAs, which regulate metabolic processes
including measures of heart rate variability and galvanic such as intestinal homeostasis, energy acquisition,
skin response, provide additional data on how the body colonocyte activity, immune system performance, and
reacts to stress and emotional stimuli. In fact, advances in other physiological functions. Despite significant
81
scientific methods have been widely applied in the study advancements in understanding the role of psychobiotics
of psychosomatic disorders, facilitating the exploration of in treating mental disorders, several questions remain
their underlying causal mechanisms and the examination unanswered, including how factors such as diet, genotype,
of correlations between brain function and clinical sex, and age influence their effects, whether psychobiotics
manifestations. 76 alter gut microbiota architecture, if their effects are short
FND, a psychosomatic disorder, has a multifactorial term or long term, their potential side effects on the
etiology, and the main risk factors for this disorder in CNS, the factors that modulate their impact, and how
adults comprise the exposition to psychological stressors they interact with psychotropic agents. On the other
as well as the previous experience of aversive episodes hand, a promising therapeutic intervention that could be
during childhood, while in children, the risk factors considered to address FND symptoms is fecal microbiota
include abuse, bullying victimization, family dysfunction, transplantation, which involves introducing fecal matter
neglect, and perceived peer pressure. 77,78 FND often from a healthy donor into the recipient’s intestinal tract to
co-occurs with other psychological conditions, such as restore the microbiota. Fecal microbiota transplantation
anxiety, depression, and post-traumatic stress disorder, as has shown effectiveness in treating recurrent Clostridioides
well as cluster B personality traits. FND is also related difficile infections and is recognized as a viable option for
79
to other functional somatic disorders, including chronic various inflammatory and mental diseases. 82
pain and irritable bowel syndrome, which suggest the In summary, gut microbes influence both the
overlapping risk factors or mechanisms shared by their enteric and CNS through the production of microbial
comorbidities. 80 metabolites and neurotransmitters. In addition, the
Undoubtedly, FND is a very peculiar health condition human microbiome is involved in neuroinflammation
that presents an important challenge for both the clinical processes. Thus, changes in the microbiome, particularly
and social ambits due to the lack of a clear understanding that of the human gut, may exert a subtle impact on the
of its etiology and pathophysiology. The absence of an cognitive and behavioral levels of individuals, as well as
identifiable neurological cause complicates its diagnosis on their brain health. The variations in the activity of
83
and treatment; this uncertainty not only makes clinical diverse brain areas in response to modifications in the
approaches difficult but also perpetuates the stigma microbiome point that the human microbiota and its
associated with mental disorders since the symptoms associated products are crucial determinants for neuronal
of individuals suffering from FND may be mistakenly coordination, an aspect involved in the pathophysiology
perceived as feigned or illusory. In social terms, this deeply of FDN. Therefore, based on these common aspects, we
affects individuals who suffer from this disorder, who postulated that stress, gut microbiome, and inflammation
often face barriers in seeking support and understanding, factors may alter the integrity of the two pivotal barriers
thereby negatively impacting their quality of life. within the gut microbiota-brain axis – the gut barrier and
Thus, recognizing these implications and promoting a the blood–brain barrier – inducing chronic and systemic
multidisciplinary approach are pivotal. In this respect, the inflammation of the brain, and causing neurological
study of the gut microbiota of patients with FND could disorders, including FND.
constitute a promising way to address this disorder, as
well as the administration of psychobiotics as a treatment Acknowledgments
could improve the related symptoms and comorbid health None.
conditions. Psychobiotics, including probiotics, prebiotics,
synbiotics, postbiotics, and parabiotics, are used to treat Funding
various neuropsychiatric and psychological disorders.
Their mechanisms of action involve immunomodulation, None.
modifying the HPA axis, synthesizing neurotransmitters, Conflict of interest
regulating BDNF, interacting with the vagus nerve,
maintaining or improving intestinal barrier function, The authors declare that they have no competing interests.

Volume 2 Issue 4 (2024) 5 doi: 10.36922/jcbp.4160