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Concept: Mass murder


Several past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts.

Concepts: Mass murder, Suicide


Abstract Adolescent mass shootings are a special subset of mass killings, which continue despite significant preventative public health efforts. It is often held that these individuals have few salient warning signs that could have been identified. This piece proposes that mass shootings committed by adolescent and post-adolescent young males must be understood from a developmental perspective. The hypothesis proposed in this paper is that such killings occur as the result of the adolescent’s frustrated effort to progress along normative development. The goal of normative separation from maternal figures by the boy is presented as a potential risk factor when this goal is thwarted. Childhood case material from the perpetrator of a recent adolescent mass shooting, the Sandy Hook shooting, is discussed as an illustration of this hypothesis. Implications for public health measures and for individualized treatment are presented and developed.

Concepts: Developmental psychology, Epidemiology, Health care, Mass murder, Adolescence, Preadolescence, Energy, Public health


Recent mass shootings by persons seemingly afflicted with serious mental illness (SMI) have received extensive news media coverage and prompted national dialogue about the causes of, and policy responses to, mass shootings. News media framing of SMI as a cause of gun violence may influence public attitudes about persons with SMI and support for gun violence prevention proposals. We analyzed the content of a 25% random sample of news stories on SMI and gun violence published in 14 national and regional news sources from 1997 to 2012. Across the study period, most news coverage occurred in the wake of mass shootings, and “dangerous people” with SMI were more likely than “dangerous weapons” to be mentioned as a cause of gun violence. (Am J Public Health. Published online ahead of print January 16, 2014: e1-e8. doi:10.2105/AJPH.2013.301557).

Concepts: Journalism, Health, News media, Mass murder, Health care, Mental illness, United States, Mass media


Recent mass killings, such as those in Newtown, Connecticut, and Aurora, Colorado, have brought new attention to mass killings in the United States. This article examines 323 mass killings taking place between January 1, 2006, and October 4, 2016, to assess how they are distributed over time. In particular, we find that they appear to be uniformly distributed over time, which suggests that their rate has remained stable over the past decade. Moreover, analysis of subsets of these mass killings sharing a common trait (e.g., family killings, public killings) suggests that they exhibit a memoryless property, suggesting that mass killing events within each category are random in the sense that the occurrence of a mass killing event does not signal whether another mass killing event is imminent. However, the same memoryless property is not found when combining all mass killings into a single analysis, consistent with earlier research that found evidence of a contagion effect among mass killing events. Because of the temporal randomness of public mass killings and the wide geographic area over which they can occur, these results imply that these events may be best addressed by systemic infrastructure-based interventions that deter such events, incorporate resiliency into the response system, or impede such events until law enforcement can respond when they do occur.

Concepts: Articles of Confederation, Probability, Event, Random variable, Mass murder, U.S. state, United States, Probability theory


This paper outlines the sociodemographic, developmental, antecedent attack, attack preparation, and commission properties of 115 mass murderers between 1990 and 2014. The results indicate that mass murderer attacks are usually the culmination of a complex mix of personal, political, and social drivers that crystalize at the same time to drive the individual down the path of violent action. We specifically focus upon areas related to prior criminal engagement, leakage, and attack location familiarity. Whether the violence comes to fruition is usually a combination of the availability and vulnerability of suitable targets that suit the heady mix of personal and political grievances and the individual’s capability to engage in an attack from both a psychological and technical capability standpoint. Many individual cases share a mixture of unfortunate personal life circumstances coupled with an intensification of beliefs/grievances that later developed into the idea to engage in violence.

Concepts: Violent crime, Murder, English-language films, Mixture model, Democide, Mixture, Mass murder, Psychology


Multicide and other mass killings are sufficiently dramatic to excite great interest from clinicians, criminologists and behavioral scientists. This paper revisits the history of the mass murderer, an entity that has progressively distinguished itself from the serial killer. The functional difference between mass and serial homicide is quite obvious, particularly in setting, time, victim status and modus operandi. Classification of these acts requires a number of parameters. The causes of mass murders are multiple and complex: although they rarely seem to be related to psychotic mental pathologies, they are always an expression of suffering that manifests itself in a psychological crisis that is both homicidal and suicidal. Several research teams have studied the sociodemographic and etiopathogenic characteristics of mass murderers and, in particular, the perpetrators of school killings. In addition to prevalent personality traits, these actions often jointly include suicides and homicides, which are brought together in the same psychic crisis. In keeping with the theory of little identity support, previous crimes influenced some mass murderers. Suicides and mass-murders are likely to be imitated. The media appears to play a crucial role in preventing the occurrence of imitation or copycat tragedies. The WHO recommendation regarding how to transcribe suicide and by extension, homicide, in the media is necessary.

Concepts: School shooting, Psychiatry, Spree killer, Crimes, Suicide, Mass murder, Murder, Homicide


Recent mass shootings in the U.S. have reignited the important public health debate concerning measures to decrease the epidemic of gun violence. Editorialists and gun lobbyists have criticized the recent focus on gun violence, arguing that gun-related homicide rates have been stable in the last decade. While true, data from the U.S. Centers for Disease Control and Prevention also demonstrate that although gun-related homicide rates were stable between 2002 and 2011, rates of violent gunshot injuries increased. These seemingly paradoxical trends may reflect the declining lethality of gunshot injuries brought about by surgical advances in the care of the patient with penetrating trauma. Focusing on gun-related homicide rates as a summary statistic of gun violence, rather than total violent gunshot injuries, can therefore misrepresent the rising epidemic of gun violence in the U.S.

Concepts: U.S. state, Mass murder, Epidemiology, United States


To examine and analyse the controversy over psychiatric aspects of the case of Norwegian far right mass murderer Anders Behring Breivik.

Concepts: Right-wing populism, Far right, Psychiatry, Political spectrum, Mass murder


This article discusses common psychological and social factors in mass murders and outlines a proposed classification system to coordinate future research efforts. The final communications of two mass murderers are analyzed to demonstrate that the forensic psycholinguistic approach may assist in providing an enhanced understanding of the motives, psychopathology, and classification of mass murderers whose offenses can seem similar from a purely behavioral perspective.

Concepts: Murder, Psychology, Mass murder