The MAOA gene encodes Monoamine oxidase A (MAO-A), an enzyme in the brain that breaks down neurotransmitters such as noradrenaline, adrenaline, serotonin, and dopamine. Neurotransmitters play a key role in mood, arousal, emotions and impulse control. People with high levels of this enzyme have less neurotransmitters and people with low levels of the enzyme have more neurotransmitters.
Variants of the MAOA gene are categorized as low-activity or high-activity. These two MAOA versions correlate with different behavioral tendencies. Low-activity variants are thought to lead to reduced levels of MAOA in the brain, possibly shifting mood by changing serotonin levels. High activity variants lead to increased levels of MAOA in the brain resulting in less neurotransmitters.
Individuals with the low activity MAOA gene, when faced with social exclusion showed higher levels of aggression than those with the high activity MAOA gene.4 Low activity MAOA could significantly predict aggressive behavior in a high provocation situation, but was less associated with aggression in a low provocation situation. 5
delinquency, crime, violence, antisocial behavior, aggression