Prevalence and patterns of psychiatric comorbidities in type 2 diabetes mellitus: a systematic review and meta-analysis

Background Type 2 diabetes mellitus (T2DM) is a global health challenge that is frequently complicated by psychiatric comorbidities, which can worsen disease outcomes and quality of life. Accurate prevalence estimates are essential to inform integrated management strategies. Objective This study aimed to systematically review and meta-analyze the prevalence and patterns of psychiatric comorbidities in individuals with T2DM. Methods A comprehensive search of PubMed, ScienceDirect, Google Scholar, and the Cochrane Library was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eligible studies included full-text, peer-reviewed articles reporting psychiatric comorbidities in adults with T2DM. Data extraction was performed independently by two reviewers. Pooled prevalence estimates were calculated using a random effects model, with heterogeneity assessed using the I 2 statistic. The search was updated through July 2025. Results A total of 12 studies met the inclusion criteria. The pooled prevalence of depression in adults with T2DM was 19% (95% CI: 14–24%), based on eight contributing studies. Mild cognitive impairment (MCI) was also frequently observed, with a pooled prevalence of 39% (95% CI: 23–59%) across four studies. Considerable variability among studies was evident, likely attributable to differences in study design, diagnostic methods, sampling frames, and population characteristics. Conclusion Psychiatric comorbidities are highly prevalent in individuals with T2DM, particularly depression and cognitive impairment, emphasizing the need for integrated psychiatric and metabolic care. This meta-analysis demonstrates that psychiatric comorbidities, particularly depression and cognitive impairment, are common in individuals with T2DM, highlighting the need for routine psychiatric screening and integrated diabetes care.