Microbiome-Gut-Brain Axis and Its Relationship to Anxiety and Depression Symptoms Among Adults with Irritable Bowel Syndrome in Abuja, North Central Nigeria

Background: The bidirectional communication pathway between the gastrointestinal microbiome and the central nervous system, termed the gut-brain axis, has emerged as a significant explanatory framework for the high psychiatric comorbidity observed in irritable bowel syndrome. Nigerian gastroenterology data addressing this relationship are virtually absent, representing a critical gap in the empirical literature. Objectives: This study aims to characterise gut microbiome diversity using 16S rRNA sequencing, quantify anxiety and depression scores using validated psychometric tools, and examine the relationship between microbiome composition and psychiatric symptom burden among adults with irritable bowel syndrome in Abuja. Methods: Forty adults with Rome IV-diagnosed irritable bowel syndrome and thirty healthy controls will be recruited at the National Hospital Abuja. Stool samples will be collected for microbiome sequencing at an accredited genomics facility. Anxiety and depression will be assessed using the Hospital Anxiety and Depression Scale. Spearman correlation and canonical correspondence analysis will examine microbiome-symptom associations. Expected Outcomes: Irritable bowel syndrome patients are anticipated to show reduced alpha diversity and compositional shifts toward pro-inflammatory genera, correlating positively with psychiatric symptom severity. Conclusion: Findings will introduce gut-brain axis research into Nigerian clinical physiology and support novel therapeutic directions. Keywords: gut-brain axis, microbiome, irritable bowel syndrome, anxiety, Abuja.