GENES AS A DEFENSE TO HOMICIDE: TRENDS IN NEUROCRIMINOLOGY

Abstract

"One of the emerging areas in the field of neurocriminology is the unearthing of a possible relationship between genes and violent criminal behaviors. Several recent studies revealed strong links between genetic variation in a monoamine oxidase gene (MAOA) and aggressiveness. The gene is responsible for translating enzymes key for catabolizing amine neurotransmitters such as dopamine, serotonin, and noradrenaline that are related to mood and behaviors. Critical changes of these genes result in Brunner syndrome characterized by lower intelligence quotient, problematic impulsive behavior, and unpredictable mood swings. Moreover, the gene has been associated with a variety of psychiatric disorders such as antisocial personality, as well as gang involvement, and a rise in weapons use. In the last two decades, a significant increase in the use of neuroscientist experts to testify in criminal proceedings has been relied upon across the United States. Based on a qualitative analysis of relevant case law, the study finds that the gene can be linked with the violent behaviors of offenders, and defense attorneys can readily get the evidence admitted at trial. However, this study shows that the behavioral genetic defense fails in two-thirds of murder cases. The extent to which genes can be blamed for antisocial behavior remains illusory. This body of court rulings suggests that the so-called “warrior gene” defense fails to exonerate an individual for homicide."