The relevance of research into functional gastrointestinal disorders (FGIDs) is determined by several interrelated factors. First, the significant prevalence of these disorders among the pediatric population, which can reach 40 %, makes them a significant problem in pediatrics and pediatric gastroenterology (Volosovets OP, Kryvopustov SP, 2022; Belousova OY, 2023). Importantly, FGIDs accompanied by abdominal pain represent 10–14 % of functional gastrointestinal disorders, which makes them a significant contributing factor to the overall pathology and leads to a decrease in the quality of life (QoL) of patients and their families (Frandemark A, 2023; MartinezGonzalez AE, 2024; Vandenplas Y, 2025).
Secondly, the modern understanding of FGIDs as disorders of the «brain — gut axis» is particularly important in the context of extreme stress, as chronic psychosocial stress caused by war is a powerful trigger for their appearance and progression (Hyams JS, 2016; Burgin D, 2022). This is confirmed by high comorbidity: about 80 % of children with FGIDs have a comorbid anxiety disorder, the prevalence of which increases rapidly in wartime (Thompson P, 2023; Liu Z, 2025).
Thirdly, persistent sleep disorders caused by traumatic experiences and stressinduced neuroendocrine dysregulation, which disturbs the balance of important neurotransmitters in the tryptophan pathway, play a key role in the pathogenesis of disorders (Semen MO, Lychkovska OL, 2023; Riga O, 2024; Marushko YV, 2025). In particular, this refers to the imbalance between serotonin (5-HT), which regulates intestinal motility, pain sensitivity, and psychoemotional state, and melatonin (MEL), which is responsible for circadian rhythms and has protective properties for the gastrointestinal tract (Matis L, 2023; Ford AC, 2024; Kim YJ, 2025).
Thus, a complex study of these mechanisms in conditions of martial law is extremely relevant for the development of new pathogenetically based approaches to the diagnosis and treatment of this pathology in children.
The aim of this study was to improve the effectiveness of diagnosis and prognosis of functional gastrointestinal disorders accompanied by abdominal pain in children in conditions of martial law by identifying pathogenetic links between psychotraumatic factors of wartime, clinical manifestations, psychoemotional sphere, neurohormonal profile, and quality of life.
The study involved 176 children of both genders who had been diagnosed with FGID accompanied by abdominal pain (functional dyspepsia (FD), n=109 (61.9 % of patients) or irritable bowel syndrome (IBS), n=67 (38.1 % of patients)) aged 6 to 18 years (17 years, 11 months, 30 days inclusive) and 30 healthy children of the same age (control group). The study was conducted from 2023 to 2025 at the pediatric department of the Kyiv City Children’s Clinical Hospital No. 2, a municipal non-profit organization, which is the clinical base of the Department of Pediatrics of the Bogomolets National Medical University (head of the department: corresponding member of the National Academy of Medical Sciences of Ukraine, Doctor of Medical Sciences, Professor Volosovets OP) and medical center «Dytina» (Kyiv).
The study consisted of two preliminary and two main stages. Its design was approved by the Commission on Bioethical Expertise and Ethics of Scientific Research at the Bogomolets National Medical University.
The preliminary stages of the research included an analysis of scientific literature on the course of FGIDs in children and its associations with neurohormonal indicators (5-
HT, MEL) and psychological characteristics, as well as the development of its methodological basis — goals, tasks, and patient selection criteria.
At the first main stage, all participants were examined for the clinical presentation of FD and IBS, as well as their clinical variants (postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), IBS with diarrhea (IBS-D), IBS with constipation (IBS-
C)), assessed sleep quality using the BEARS scale, anxiety levels using the SCARED-C questionnaire, and QoL indicators using the PedsQL™ 4.0 questionnaire, followed by a cross-group comparative analysis. In the second stage, 74 children were randomly selected from the main group to measure 5-HT levels in blood serum and MEL in saliva. The results were compared with similar indicators in the control group. Biochemical studies were performed in the laboratory of the Science and Research Institute of Experimental and Clinical Medicine of the Bogomolets National Medical University in agreement with a scientific cooperation contract.
