Effects of DNA methylation and polygenic scores on self-reported suicidal ideation in psychoses: no evidence of epigenetic basis of polygenic risk

Introduction Schizophrenia is a significant clinical problem. Unfortunately, there are currently no biomarkers available for accurately identifying patients with schizophrenia who may be vulnerable to suicide. Because genetic and environmental factors play a role in suicide, we attempted to determine the role of DNA methylation and polygenic risk scores in the relationship to suicidal ideation. Methods Using a cross-sectional study design, 98 participants with schizophrenia spectrum disorders were interviewed, and suicidal ideation was assessed using the Beck Scale for suicidal ideation, and whole blood was collected for methylation analysis. Results Our analysis showed a correlation between cg21813303 methylation and suicidal ideation, but this association did not reach genome-wide significance. The polygenic risk scores for suicidality were not associated with schizophrenia severity, and no biological relationship was found between DNA methylation and polygenic risk scores. Conclusion This pilot study indicates that it is unlikely that DNA methylation and polygenic scores can predict suicidal ideation in schizophrenia.