Paranoid thinking in mass shooters

Abstract Mass murderers, particularly school shooters, are depicted in the literature as either reacting with rage to taunts and bullying or as being psychopathic. However, examination of diaries and Web sites left by a subset of mass shooters (e.g., Eric Harris, Kimveer Gil, Seung-Hui Cho, Anders Breivik) reveals a different phenomenology than that typically proposed. This group greatly exaggerates the negativity of their treatment as reported by third-party school peers. They become and remain fixated and obsessed with rejection by what they see as an elite in-group whom they see as having unfairly achieved success. Instead of transcending the rejection, they formulate plans to annihilate the transgressors, which they justify as vengeance for the transgressions made against them. The self-exacerbating and obsessive qualities of these perceptions are more consistent with paranoid thinking than with psychopathy. The perceptions feed on themselves and, being part of a closed belief system, expand with time. In the rare cases where the perpetrator survives the mass shooting, they are diagnosed as paranoid schizophrenic. We focus on the pre-psychotic deterioration of their thinking.