Authors: Ashraf alshaloudi , Gharam Abdulaziz Alahmadi , Mohamad Bassel Dahha , Layan Hamed Alahmadi , Buthaynah Abdurhman Almaawi , Abdulrahman Abdullah Somaan , Abdullah Abdulrahman Alqasem , Faris Mohammed Jahlan , Abdulrahman Yahya Alwadie , Shadi Hamad Abbod , Asim Mohammed Alasmari , Saeed zamil alasmari

Abstract

Background: Functional gastrointestinal disorders (FGIDs), particularly irritable bowel syndrome and Functional Dyspepsia (FD), represent a significant burden on the Saudi healthcare system. Emerging evidence implicates the Gut–Brain Axis and vagal tone dysregulation in their pathophysiology. This systematic review aims to synthesize existing evidence regarding the prevalence and magnitude of the association between FGIDs and psychological comorbidities (anxiety, depression) among adults in Saudi Arabia, framing these findings within the context of vagus nerve dysfunction.
Methods: A systematic literature search was conducted, adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines across PubMed, Scopus, and Google Scholar (2017–2026). Inclusion criteria were observational studies involving Saudi adults with diagnosed FGIDs reporting psychological outcomes. Methodological quality was rigorously assessed using the Newcastle–Ottawa Scale.
Results: Twenty observational studies (N = 12,186 participants) met the inclusion criteria. Synthesis of data revealed a high prevalence of comorbidity: anxiety and depression were reported in 56% of studies as primary outcomes. Gastroesophageal Reflux Disease and FD were the predominant Gastrointestinal phenotypes. Quality assessment indicated a moderate risk of bias, primarily due to cross-sectional designs.
Conclusion: There is robust evidence of a bidirectional relationship between FGIDs and psychological distress in the Saudi population. While local studies confirm the clinical association, the mechanistic role of the vagus nerve is strongly supported by extrapolating international physiological data to this confirmed clinical phenotype. Integrated psychogastroenterology clinics are recommended.

Keywords: Saudi Arabia, irritable bowel syndrome, functional dyspepsia, GERD, gastrointestinal diseases, anxiety, depression, psychological distress, mental health, vagus nerve, gut-brain axis, parasympathetic.