Prevalence of major depressive disorder in the general population of Iran: A systematic review and meta-analysis

Major depressive disorder (MDD) is the most common psychological disorder and affects many people worldwide. Surveying the prevalence of mental disorders, especially general disorders, such as major depressive disorder, is highly important for health professionals and policymakers. Due to a wide variation of studies concerning the prevalence of major depressive disorder in Iran, the present study was conducted to integrate such results. 

To conduct this study, English (PubMed/Medline, Scopus and Web of Science) and Persian (MHRN, Noormgs, Magiran, Iran-Medex, Irandoc, and SID) databases, from 1990 to 2018, were explored. All articles related to the point prevalence of depressive disorders in the general population of Iran were reviewed. The inclusion criteria of the present study were as follow: cross sectional studies based on general populations; the expression of the point prevalence rate and incidence of major depressive disorder for people over 15 years; and the use of a structured or semi-structured clinical interview for diagnosis of the disorder. Studies that were not original (such as review studies) and those that did not represent general populations were excluded from the study. To analyze the data obtained from this study, the second version of Comprehensive Meta-Analysis (CMA) software was used. The total point prevalence was calculated using the meta-analysis method, and the I2 index was used to measure the heterogeneity of the studies.

Of 6734 studies, 30 studies with a total sample size of 37 867 were finally included based on proposed inclusion and exclusion criteria. The sample included 20641 women (55%), and 17 226 (45%) men. In the present meta-analysis study, due to significant heterogeneity (I=97.1%, p=0.001) among studies, the randomized method was used, and the total point prevalence was 4.1% (CI: 3.1% 5.5%). The overall point prevalence of major depressive disorder was 4.8% (CI: 3.6% -5.6%) in women and 2.3% (CI: 1.6% -3.6%)in men, which indicated that the incidence of this disorder was 1.95 times more in women than in men.

This meta-analysis study found a considerable prevalence of major depressive disorder among Iranian participants and revealed that the point prevalence of the disease was more than two-fold in women compared to men. Considering these findings and the high burden of this disorder for communities, the need to formulate and implement prevention and treatment programs is highly required.