INS and depressive disorder: Liu et al. [15] found that the pooled prevalence of comorbid depression among T2DM patients in China was 25.9% (95% CI: 20.6–31.6%), with the figure being higher in females, participants aged ≥60 years, those with a primary school or lower education, individuals with a duration of T2DM ≥10 years, participants with diabetic complications, insulin users and participants living alone, and being lower in those with current alcohol use.