Association between selective serotonin reuptake inhibitor use and developing irritable bowel syndrome through retrospective analysis

Background and Aim: Serotonin affects the balance and integrity of the gut microbiome; however, studies have confirmed the influence of selective serotonin reuptake inhibitors (SSRIs) on irritable bowel syndrome (IBS). We evaluated the association between SSRI use and subsequent IBS occurrence in a real-world setting. Methods: A multivariate Cox proportional hazard model was adopted, and the National Health Insurance Service cohort claims database between 2010 and 2019 was used. Non-SSRI users were selected using the propensity score matching method. Subgroup analyses were performed using the point of use, cumulative dose, and duration of SSRI use. Additional analysis was performed using a control group without psychiatric medications. Results: We included 2901 SSRI users and 2727 non-SSRI users. After adjusting covariates, the risk of developing IBS in SSRI users was 1.54 times that in non-SSRI users (95% confidence interval [CI]: 1.01–2.33). The hazard ratio (HR) of the recent, heavy, and short-term user groups were 3.19 (95% CI: 2.03–4.99), 2.22 (95% CI: 1.50–3.29), and 4.83 (95% CI: 3.02–7.73), respectively, compared with that of non-users. In patients without a history of psychiatric medications, the risk of IBS incidence after SSRI use increased significantly (HR: 1.61, 95% CI: 1.06–2.42), whereas HR was insignificant in patients with a history of psychiatric medications (HR: 1.25, 95% CI: 0.98–1.60). Conclusions: The risk of subsequent IBS occurrence following SSRI use was high in patients who initially took a heavy SSRI dose and those who did not have a history of psychiatric drug use.