Violence is rare in autism: when it does occur, is it sometimes extreme?

A small body of literature has suggested that, rather than being more likely to engage in offending or violent behavior, individuals with autism spectrum disorder (ASD) may actually have an increased risk of being the victim rather than the perpetrator of violence (Sobsey, Wells, Lucardie, & Mansell, 1995). There is no evidence that people with ASD are more violent than those without ASD (Im, 2016). There is nevertheless a small subgroup of individuals with ASD who exhibit violent offending behaviours and our previous work has suggested that other factors, such as adverse childhood experiences, might be important in this subgroup (Allely, Minnis, Thompson, Wilson, & Gillberg, 2014). Fitzgerald (2015) highlights that school shootings and mass killings are not uncommonly carried out by individuals with neurodevelopmental disorders, with frequent evidence of warning indicators. The aim of the present review is to investigate this in more detail using the 73 mass shooting events identified by Mother Jones (motherjones.com) in their database for potential ASD features. There are 73 mass shooting events but there are two events where there is a pair of shooters which meant that 75 mass shooter cases were investigated. This exercise tentatively suggests evidence of ASD in six of 75 included cases (8%) which is about eight times higher when compared to the prevalence of ASD found in the general population worldwide (motherjones.com). The 8% figure for individuals with ASD involved mass killings is a conservative estimate. In addition to the six cases which provide the 8% figure, there were 16 other cases with some indication of ASD. Crucially, ASD may influence, but does not cause, an individual to commit extreme violent acts such as a mass shooting episode