A major hindrance to determining the underlying biology of suicide is the heterogeneity of the phenotype. Not only are there various forms of self-harm and suicidal behaviors but even the finite act of dying by suicide can occur in multiple psychosocial contexts. Of all the different forms of fatal and non-fatal suicidal behaviors, the one that received the most attention is the aggressive impulsive type, which seems to occur in younger people and to cut across nosological entities, although its most classical expression occurs in borderline personality disorder. This focus should not obscure the fact that other forms of suicidal behavior such as those related to demoralization or wounded honor (narcissism) may well have different underlying genetic diatheses.