Risk Factors of Depression Screened by Two-Sample Mendelian Randomization Analysis: A Systematic Review.

Objective: This study explored the potentially modifiable factors for depression and major depressive disorder (MDD) from the MR-Base database and further evaluated the associations between drug targets with MDD.

Methods: We analyzed two-sample of Mendelian randomization (2SMR) using genetic variant depression ( n = 113,154) and MDD ( n = 208,811) from Genome-Wide Association Studies (GWAS). Separate calculations were performed with modifiable risk factors from MR-Base for 1,001 genomes. The MR analysis was performed by screening drug targets with MDD in the DrugBank database to explore the therapeutic targets for MDD. Inverse variance weighted (IVW), fixed-effect inverse variance weighted (FE-IVW), MR-Egger, weighted median, and weighted mode were used for complementary calculation.

Results: The potential causal relationship between modifiable risk factors and depression contained 459 results for depression and 424 for MDD. Also, the associations between drug targets and MDD showed that SLC6A4, GRIN2A, GRIN2C, SCN10A, and IL1B expression are associated with an increased risk of depression. In contrast, ADRB1, CHRNA3, HTR3A, GSTP1, and GABRG2 genes are candidate protective factors against depression.

Conclusion: This study identified the risk factors causally associated with depression and MDD, and estimated 10 drug targets with significant impact on MDD, providing essential information for formulating strategies to prevent and treat depression.