Three additional studies extend the Caspi et al.2 findings: one was a prospective investigation of 631 male and female, and white and black victims of (court-substantiated) child abuse and neglect, along with a comparison group matched on age, sex, race/ethnicity and social class background;20 the second one a retrospective study of 235 adult psychiatric outpatients and healthy controls who reported on trauma experienced in childhood and physical aggression in adulthood;21 and the last one a cross-sectional retrospective study with an American Indian sample of 291 adult women, 50% of whom had a history of childhood sexual abuse.22 White (but not black) males and females with the low-MAOA-activity allele in the longitudinal study manifested the most lifetime violent and antisocial behavior during adolescence, as well as around age 40, if they had been maltreated, but the least (at both times of measurement) if they had not been victims of abuse. In the second study, men (only) with the low-MAOA-activity variant reported more physical aggression if they experienced one or more (retrospectively reported) objective traumatic events while growing up (for example, death
