It is well established that suicidal ideation and the act of suicide are associated with a variety of psychiatric disorders, including substance use disorders (SUD). While depression has been most commonly shown to covary with suicidality, externalizing disorders have also been shown to be present. There is a frequent co-occurrence between suicide and (SUD), however, it has not been resolved how much of this association is due to specific factors intrinsic to SUD and how much is due to other psychiatric factors. While the covariation between SUD and suicide has been shown, the mechanisms underpinning this relationship have not been investigated. Four patterns of covariation may exist: 1) genetic and/or environmental factors underlying the liability for SUD may be the same factors underlying the liability for suicide; 2) the biobehavioral consequences of substance consumption particularly psychiatric disorder and stress, increase the risk for suicide; 3) suicidal propensity promotes substance use that over time culminates in a DSM diagnosis of abuse; and 4) SUD and suicide are not causally related but reflect a rate of co-occurrence consistent with their conjoint probability. The goal of this study is to determine the extent to which SUD and suicidality have a common liability. One hundred twelve 19-year old male subjects participated in this study. The subjects were tested at age 10-12 and followed-up at age 19 when SUD and suicidal outcomes were documented. The findings showed that psychological dysregulation in childhood was a risk factor for SUD but not suicidality. Children of men with SUD did report a higher rate of suicidal ideation and attempts compared to the children of psychiatrically normal men. This demonstrated that the risk of suicide and SUD did not completely map to each other; there may be unidentified factors that were associated with both outcomes. Tables, references