MAO-A gene

• What is the MAO-A gene ?

  Produces the enzyme monoamine oxidise-A which metabolises seretonin
• A variant of this gene produces lower levels of the MAO-A gene leading to an increase of Seretonin, overtime the brain becomes desensitised to the calming effects of seretonin, this leads to aggressive and impulsive behaviour
• Individuals with low levels of MAO-A activity are more likely to engage in criminal behavior.
• The MAO-A gene, also known as the "warrior gene," is associated with aggressive and impulsive behavior.
• Key study - Brunner et al 


  large family in the Netherlands with a history of violent aggressive behaviour

  analysed 28 members and found the violent men shared the MAO-A gene, this was not the case for the non violent men.