Richter D, et al. - Researchers conducted a meta-analysis to examine the trend of mental illness prevalence rates. Forty-four samples from 42 publications were included in this work; these represent 1,035,697 primary observations for the first time point and 783,897 primary observations for the second and last time point. Observations revealed an increase in overall global prevalence in the odds ratio of 1.179, controlling for a hierarchical data structure. As per the multivariate meta-regression, relevant associations with methodological characteristics of the included studies were noted. These findings suggest a small increase in the prevalence of adult mental illness, and it seems that demographic changes are mainly related to this increase.