ABSTRACT
The imaging genetic studies in patient samples provide further evidence of a role for Monoamine oxidase A gene (MAOA) in impulsive-aggression and related traits. Aggression in animals is often characterized as being either “functional” or “pathological” in nature, and this distinction may also be applicable to human work. Functional aggression is contextually appropriate and constrained by species-specific rules and rituals; the ritualized violence of professional sports perhaps represents a human analog of this functional aggression. A body of behavioral genetic data provides qualified support for the notion that lowered MAOA expression predisposes disinhibitory psychopathology. Researchers have sought to investigate the role of MAOA genetic variation on brain circuits, and have found that MAOA-L carriers have dysregulated corticolimbic circuitry for affective arousal and inhibitory control. Considerable evidence suggests that functional genetic variation in MAOA disrupts corticolimbic circuitry for affective arousal and regulation and, in turn, predisposes risk for impulsive-aggression.
