A new study published in the International Journal of Biological Sciences examined the presence and severity of depressive symptoms in patients with irritable bowel syndrome (IBS). Here, a literature search was conducted; pooled depressive symptom severity was calculated using a random effects model. Subgroup, sensitivity and meta-regression analyses were performed to examine the moderating factors of the development of depressive symptoms. Overall, 24 studies, comprising 2,837 patients, comparing depressive symptoms between 1,775 IBS patients and 1,062 healthy controls were selected; 14 studies were rated as high quality. The findings revealed that when compared to healthy controls, IBS patients had more frequent and more severe depressive symptoms. Subgroup analyses revealed that patients with all IBS subtypes had more severe depressive symptoms than controls. Meanwhile, versions of the Hamilton Depression Rating Scale (HAM-D) and IBS diagnostic criteria were significantly associated with depressive symptom severity. Female gender, younger age and small sample size were significantly associated with more severe depressive symptoms. The findings indicated that IBS patients have more frequent and severe depressive symptoms than healthy controls. It was stated that adequate screening and treatment for depression should be developed and implemented in this patient population.