Recently, genome-wide association studies (GWAS) of suicidality have been conducted in large cohorts, identifying several risk loci and strong genetic overlap with depression4–8. However, to our knowledge, no gene-by-environment genome-wide interaction studies (GEWIS) have yet been conducted to evaluate the genetic interplay between suicidality and SDs. In the context of gene-by-environment interaction studies, environmental risk factors can include exposures (physical, chemical, biological), behavioral patterns, or life events9. We previously showed that this approach is useful to identify the complex interactive mechanisms linking genetic background with the interplay between SDs and psychiatric and behavioral phenotypes10–13. To explore the phenotypic association of different SDs with the suicidality spectrum, we investigated multiple SDs (testing for each SD the individual effect independent from the other SDs; and the cumulative effect of having received multiple SD diagnoses) with respect to suicidal ideation (SI), suicide planning (SP), and suicide attempt (SA). Subsequently, we conducted a discovery GEWIS to verify whether SDs interact with the individual genetic variability in the context of SI. Finally, based on the high genetic overlap between suicidality and depression observed across multiple
