Causal associations between sexually transmitted infections, depression, and self-harm: a mendelian randomization and cross-sectional study.

Background: The causal relationships between sexually transmitted infections, depression, and self-harm remain unclear.

Methods: We executed various Mendelian Randomization (MR) analyses. At the same time, a cross-sectional analysis from NHANES was used for verification and an enrichment analysis was also utilized to explore the potential common gene functions.

Results: We found that STIs may have a potential causal effect on depression (P = 0.002) and self-harm (P = 0.003). Conversely, self-harm has been identified as a risk factor for the acquisition of STIs (P = 0.006), while there is no evidence to support an effect of depression on STIs. Furthermore, mediation MR indicated that monocyte absolute count played a mediating role in the association between STIs and depression, accounting for 7.7%. And then, the weighted regression analysis of the cross-sectional analysis demonstrated a significant association between one of the common STIs, HPV, and depression. Gene enrichment analysis suggested that the PI3K-Akt signalling pathway and the infectious virus signalling pathway may represent a common underlying pathogenesis.

Conclusion: STIs may increase the risk of depression and self-harm, while self-harm might also represent a risk factor for STIs, which could provide insights and a foundation for the control of STIs and mental health monitoring in clinical practice.