Deficits in cognitive-neuropsychological abilities have been viewed as contributing to an impulsive behavioral style in a brain-environmental interaction (Moffitt, 1993; Squin et al., 1995). The authors of several recent literature reviews unanimously conclude that impairments in executive cognitive functions are implicated in the regulation of impulsive aggressive behavior (Buikhuisen, 1987; Hurt and Haglieri, 1992; Kandel and Freed, 1989; Lueger and Gill, 1990; Milner, 1991; Moffitt, 1990, 1993; Moffitt et al., 1994; Pennington and Bennetto, 1993). The prefrontal cortex and some of its subcortical connections represent the neural substrates most involved in subserving executive cognitive functioning, suggesting their involvement in concomitant aggressive behavior; however, it is possible that various forms of aggression are associated with distinctive causes and varying neural substrates. In the pilot data presented in this article, all three instruments had scores related to history of violence, implicating the involvement of multiple brain regions. The logical next step in future research is to directly measure neural responses in particular brain regions to various cognitive challenges in individuals with and without violent behavior and substance abuse. 3 notes and 127 references