A Preliminary Report on Alcohol-Associated DNA Methylation Changes and Suicidal Behavior: Evidence Using Mendelian Randomization

Suicide is a major public health concern. In 2015, it was the 10th leading cause of death in the US. The number of suicides increased by 30% in the US from 1999 to 2016, and a greater uptick in suicides is predicted to occur as a result of the COVID-19 crisis, for which the primary public-health strategy is physical distancing and during which alcohol sales have soared. Thus, current strategies for identifying at-risk individuals and preventing suicides, such as relying on self-reported suicidal ideation, are insufficient, especially under conditions of physical distancing, which exacerbate isolation, loneliness, economic stress, and possibly alcohol consumption. New strategies are urgent now and into the future. To that aim, here, a two-sample Mendelian randomization (an instrumental variables technique using public genome-wide association study data as data sources) was performed to determine whether alcohol-associated changes in DNA methylation mediate risk for suicidal behavior. The results suggest that higher alcohol-associated DNA methylation levels at cg18120259 confer a weak causal effect. Replication and triangulation of the results, both experimentally and with designs other than Mendelian randomization, are needed. If the findings replicate, the information might be utilized to raise awareness about the biological links between alcohol and suicide and possibly explored as a biomarker of risk, perhaps especially for early detection of those who may not self-report suicidal intent.