MAO-A Serotonin and Aggression | MindLAB Neuroscience
Serotonin, MAO-A, and the Genetics of Conflict Escalation: Why Some Brains Are Neurochemically Primed for Aggression The MAO-A gene — specifically its low-activity variant — reduces the brain’s ability to metabolize serotonin at the synapse, starving the prefrontal cortex of the neurochemical fuel it requires to inhibit impulsive aggression. This is not a metaphor. Monoamine oxidase A — the enzyme responsible for breaking down serotonin, dopamine, and norepinephrine after release — operates at measurably different efficiencies depending on which allele a person carries. When combined with early adversity, this genetic variation produces a compound vulnerability: the prefrontal brake that prevents escalation during conflict literally runs on a reduced fuel supply. In 26 years of practice, I observe the downstream behavioral signature of this mechanism with striking consistency — individuals whose conflict escalation is predictable, intense, and genuinely bewildering to them afterward. ...
