Suicide and related behaviors are complex phenomena associated with different risk factors. While most individuals who display suicidal behavior do not have a history of early-life adversity, a significant minority does. In this symposium, Dr. Turecki will discuss results from his laboratory suggesting that early-life adversity increases risk of suicide by altering methylation patterns in discrete genetic loci. Stable gene expression resulting from these altered methylation patterns are likely to influence the development of stable emotional and behavioral phenotypes that, in turn, increase suicide risk. He will discuss recent data suggesting that these mechanisms are at play in the regulation of aggressive behavior.