Constipation is associated with an increased risk of depression: A systematic review and meta-analysis of observational studies

BACKGROUND: Constipation is a prevalent functional gastrointestinal disorder that impairs quality of life and is frequently accompanied by psychological distress. Emerging evidence suggests a potential association between constipation and depression, possibly mediated by gut-brain axis dysfunction; however, epidemiological findings remain inconsistent. METHODS: We conducted a systematic review and meta-analysis of observational studies examining the association between constipation and depression in the general population. PubMed, Web of Science, Embase, and the Cochrane Library were searched from inception to October 1, 2025. Random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (CIs). Heterogeneity, prediction intervals, subgroup analyses, sensitivity analyses, and publication bias were assessed. RESULTS: Eighteen studies involving 730,263 participants were included. Constipation was significantly associated with an increased risk of depression (OR = 2.08, 95% CI: 1.84-2.34), with substantial heterogeneity (I² = 92.6%). The association remained robust across sensitivity analyses. Stronger associations were observed in adolescents, in studies conducted in Asia and North America, in smaller studies, and in those using self-reported depression measures. Prediction interval analyses indicated a consistently positive association across diverse populations. CONCLUSIONS: This meta-analysis provides robust evidence that constipation is associated with a significantly increased risk of depression. These findings highlight the importance of integrated gastrointestinal and mental health care, particularly for younger individuals with chronic constipation, and support further prospective and mechanistic studies targeting the gut-brain axis.