Brain-Gut Interplay: Cognitive Performance and Biomarker Correlations in IBD Patients

<b>Background/Objectives:</b> Inflammatory bowel diseases (IBD), including mainly ulcerative colitis (UC) and Crohn's disease (CD), have been associated with cognitive and psychological changes, though the mechanisms remain unclear. <b>Methods</b>: This prospective case-control study aimed to evaluate cognitive performance and biomarkers (homocysteine, serum amyloid A, brain-derived neurotrophic factor, and S100B protein) in IBD patients. <b>Results</b>: A total of 90 individuals (34 UC, 21 CD, and 35 controls) were assessed using the Montreal Cognitive Assessment (MoCA), the Memory Impairment Index (MIS), and biomarker analysis. MoCA and MIS testing showed significant differences between UC, CD, and the controls, with lower scores observed in IBD groups (<i>p</i> = 0.003, <i>p</i> = 0.015). Regarding trail-making tests, digit symbol substitution tests, and forward and backward digit spans, no significant changes were observed. No functional deficits were observed in daily activities. Biomarker analysis revealed lower brain-derived neurotrophic factor and higher serum amyloid A levels in IBD patients, correlated to MOCA and MIS scores. There were no significant differences in psychological distress between IBD patients and the controls. Subtle cognitive declines were noted across all groups during the 1-year follow-up, without any statistical significance when groups were compared. <b>Conclusions</b>: In conclusion, IBD patients reported lower cognitive scores compared to the controls, while no differences in depression and anxiety scores were observed. Higher BDNF levels correlated with better cognitive functioning, while higher serum amyloid A correlated with lower cognitive functioning.