Monoamines & Violent Criminal Behavior

Monoamines in the human brain are phylogenetically ancient neurochemicals, also broadly found in various organisms such as squid, turtles and flowers, etc. Monoamines dopamine and serotonin can be indirectly derived too from foods we eat such as fish, nuts, mushrooms and (you guessed it) chocolate.

In the brain, monoamines are produced from the substantia nigra (dopamine) and dorsal raphé (serotonin), mid-brain regions near the brain stem, ancient regions compared to our relatively modern frontal cortices. Monoamines calibrate the relative contribution of all other neurochemicals, like lubricant ‘WD-40’ for our brain. And the expression of monoamines plays a role in violent criminal behavior too.

Dopamine is associated with motivation, reward and risk-taking; the neurochemical of gambling. The risk taking continuum, ranging from apathetic complacency to reckless dare-devilling confer personality qualities, and, yes, violent aggressors can reach the far-end. Still, risk-taking can be a hallmark of great achievement too! Imagine astronauts fearlessly venturing into outer space, Antarctic explorers and shark divers, etc. Serotonin modulates mood, instilling a sense of contentment. Intentionality contextualizes how monoamines are expressed.

Monoamine oxidase A is a special enzyme that metabolizes dopamine and serotonin. Historical research found that the gene coding for this enzyme is defective in violent aggressors. No single gene underlies violent criminal behavior, of course, but subsequent studies are compelling. In sum, high levels of dopamine potentiates aggression. Conversely, low levels of serotonin in conjunction with other risk factors can result in violent aggression.

Brains are complex, and, by extension, linking brain chemistry to violence is complicated. Understanding how monoamines work in the human brain sheds light on the underpinnings of violent criminal behavior.

By A. Du Beau 2019


Dr Amy Du Beau
Anchorage, Alaska
ph. 907-644-2929
c. 907-312-8687


Du Beau A., Matanuska Forensic Science, LLC.