This study explored the interaction of the aforementioned variables in the genesis of violence. Subjects were six adopted murderers for whom data could be obtained on biological and adoptive parents. In all six cases, central nervous system (CNS) development was compromised in utero or perinatally. In adolescence and/or young adulthood, three met DSM-IV criteria for Bipolar Mood Disorder, one for Schizophrenia, and two for Schizoaffective Disorder. All subjects had at least one psychotic biological parent. In five cases, subjects were adopted into psychotic or violent households. There was no evidence of a specific "bad seed" for violence. Adoptees' intrinsic vulnerabilities to psychoses and to the impulsiveness and emotional change often associated with early brain trauma, coupled with maltreatment, predisposed them to homicidal violence. As such, these subjects were similar to other extraordinarily violent, nonadopted offenders. Conscious feelings regarding adoption did not contribute to the subjects' homicidal rages as much as did conscious rage toward abusive, rejecting adoptive families. The authors advise that the extent to which these findings are characteristics of other adopted children who murder remains to be explored further. 3 tables and 22 references