Causal relationship between rosacea and psychiatric disorders: a bidirectional two-sample Mendelian randomization study

This study investigated the causal association between rosacea and psychiatric disorders, including major depression disorder (MDD), anxiety disorder (AD), and panic disorder (PD). A bidirectional two-sample Mendelian randomization (MR) analysis was performed. The publicly released genome-wide association summary data (GWAS) of rosacea and psychiatric disorders was used in the MR analysis. The random-effects inverse variance weighted method (IVW) was applied as the primary method, and several other estimators were used as complementary methods. MR-Egger, MR-PRESSO, Cochran's Q, and leave-one-out were performed to evaluate sensitivity and robustness. The forward MR results suggested that genetically determined rosacea did not have a causal association with the three psychiatric disorders. In the reverse analysis, the MR analyses consistently showed non-significant causal effects of these psychiatric disorders on rosacea. These findings were robust across different analytical methods. Sensitivity analyses confirmed the consistency of the results and provided no evidence of horizontal pleiotropy or outliers. A validation analysis using different datasets for the exposures and the outcomes, supporting the initial MR analysis results. Overall, the study found no evidence of a bidirectional causal relationship between genetically predicted rosacea and three psychiatric disorders despite observational studies reporting an association between rosacea and psychiatric disorders. The causal effects between these diseases need further exploration.