This study employs the Mendelian Randomization (MR) approach to explore the potential causal relationship between schizophrenia and the risk of developing narcolepsy.Genome-Wide Association Studies (GWAS) data from European populations were used to identify independent genetic variants associated with schizophrenia and narcolepsy, which were then used as instrumental variables in the analysis. The inverse variance weighting (IVW) method was performed to validate the findings. Effect sizes were presented as odds ratios (OR) and beta coefficients (β).The IVW analysis showed no significant causal relationship between schizophrenia and narcolepsy (OR: 1.002, 95 % CI: 0.996-1.007, P = 0.531). Likewise, the reverse analysis did not find any significant causal association (OR: 1.059, 95 % CI: 0.717-1.567, P = 0.421). Sensitivity analyses further confirmed the robustness of these findings.The MR analysis does not provide evidence for a bidirectional causal relationship between schizophrenia and narcolepsy. Further research is needed to elucidate the underlying mechanisms and to identify potential targets for intervention.Copyright © 2024 Elsevier B.V. All rights reserved.