Why do people commit mass murder?

Neurodevelopmental and psychosocial risk factors in serial killers and mass murderers Institute of Health and Wellbeing 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.