Why do people commit mass murder?

(Medical Xpress)—Mental health specialists at the University of Glasgow have conducted the first review of published research into what causes people to undertake serial killings and mass murder.

The report, which is the first of its kind to look at all the available material around serial and mass killers, identified that a complex interplay between neurodevelopmental problems and psychosocial factors are most likely to lead to incidences of this kind.

The report's main findings are that:

• 28% of eligible killers were suspected to suffer from Autism Spectrum Disorder (ASD).
• 21% of eligible killers had suffered a definite or suspected head injury in the past.
• Of those killers with ASD and/or head injury, 55% had experienced some psychosocial stressors in the past.

The findings, published in the Journal of Violent and Aggressive Behavior, show a relationship between neurodevelopmental disorders, such as ASD or head trauma, and psychosocial disorders, such as exposure to physical or sexual abuse during childhood. The researchers note that a person suffering a neurodevelopmental disorder or a brain injury by itself does not result in a serial killer or mass murderer.

Researchers also note that research into mass and serial killings is still at a rudimentary stage and that new research is urgently required so that preventative strategies can be developed. The paper recommends the design and implementation of a system of standardised tools for investigating all instances of mass and serial killings in the future.

Lead researcher, Dr Clare Allely, from the Institute of Health and Wellbeing at the University of Glasgow, said: "It is crucial to note that we are not trying to suggest that individuals with ASD or previous head trauma are more likely to be serial killers or commit serious crime. Rather we are suggesting that there may be a subgroup of individuals within these groups who may be more likely to commit serious crimes when exposed to certain psychosocial stressors.

"Research on mass and serial killing is still very much in its infancy. New research is urgently required to understand the mechanisms underlying these extreme forms of violence so that preventative strategies can be developed. We would recommend that in future, all serial or mass killers who are apprehended should be thoroughly assessed using standardised tools for investigating neurodevelopmental disorders including ASD and head injury."