Mass Murder: An Understanding of Its Causes and Prevention


  • Silvio José Lemos Vasconcelos Departamento de Psicologia da Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brasil
  • Lisiane dos Santos Welter Departamento de Psicologia da Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brasil
  • Thamires Pereira Barbosa Departamento de Psicologia da Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brasil
  • Luiza Vieira Macedo Pinto Departamento de Psicologia da Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brasil
  • Rafaella Valli Santanna Departamento de Psicologia da Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brasil
  • Eduarda Portella Quevedo Departamento de Direito da Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brasil
  • Fernanda de Vargas Departamento de Ciências Criminais da PUCRS, Santa Maria, RS, Brasil



Juridical psychology, Mass murder, Mental health.


Mass murder is defined when at least three or four murders occur at the same time and in the same place. Occurrence occurs in a short period of time, within a few hours, and in a single location or in nearby areas, such as work, leisure or school. In Brazil, despite recent episodes, the subject is still little investigated, mainly by psychologists. Brazilian scientific production on mass killings is really scarce. This article aims to elucidate the current state of knowledge on the subject. The authors perform a non-systematic review of epidemiological and social studies on the topic. The occurrence of mass killings can be understood from a biopsychosocial understanding, including psychotic symptoms that drive crime. Issues of prevention on the international stage are also addressed in this article. This study can contribute to boost national scientific production on the subject and generate timely reflections on the prevention of similar problems.


Uol. (2018). Homem mata 4 pessoas dentro de Catedral em Campinas (SP) e se suicida.Uol. [publicação online]. 2018 [acesso em 10 mar. 2021]. Disponível em

Uol. (2019). Cronologia de ataques a tiros em escolas do Brasil.Uol. [publicação online]. 2019 [acesso em 10 mar. 2021]. Disponível em

Guaíba (2020). Polícia Civil investiga se autor da chacina em Santa Catarina teve ajuda. Guaíba. [publicação online]. 2021 [acesso em 14 maio 2021]. Disponível em

Knoll JL. Mass Murder: Causes, Classification, and Prevention. Psychiatric Clinics of North America. 2012;35(4):757-80.

Imai H, Ogawa Y, Okumiya K, Matsubayashi K. (2019). Amok: a mirror of time and people. A historical review of literature. History of Psychiatry. 2019; 30(1):38-57.

Brasil. Código Penal 2008. Decreto-Lei nº 2.848, de 7 de dezembro de 1940. Vade mecum. São Paulo, SP: Saraiva.

Dalgalarrondo P. Psicopatologia e semiologia dos transtornos mentais. 2. ed. Porto Alegre: Artmed; 2008. 271 p.

Hutz CS, Bandeira DS, Trentini CM, Krug JS. Psicodiagnóstico. 1. ed. Porto Alegre: Artmed; 2016. 428 p.

Gill P, Silver J, Horgan J, Corner E. Shooting Alone: The Pre-Attack Experiences and Behaviors of U.S. Solo Mass Murderers. Journal of Forensic Sciences. 2017; 62(3):710-14.

Sarteschi CM. Severe Mental Illness, Somatic Delusions, and Attempted Mass Murder. Journal of Forensic Sciences. 2016;61(1):284-7.

Knoll JL, Meloy JR. Mass murder and the violent paranoid spectrum. Psychiatric Annals. 2014; 44(5): 236-43.

Peter E, Seidenbecher S, Bogerts B, Dobrowolny H, Schöne M. Mass murders in Germany - classification of surviving offenders based on the examination of court files. The Journal of Forensic Psychiatry & Psychology. 2019;30(3):381-400.

Winter D, Tschudi F. Construing a "Perfect Knight": A Personal Construct Investigation of Mass Murder. Journal of Constructivist Psychology. 2015;28(2): 139-51.

Feis J, Feist GJ, Roberts TA. Teorias da Personalidade. 8. ed. Porto Alegre: Artmed; 2015. 464 p.

Hamad E, Johnson A, Kinsella E. Reconstruction of existing constructs: A personal construct theory approach for cross-cultural construing of quantitative measures. Personality and Individual Differences. 2016;101:483.

Taylor MA. A Comprehensive Study of Mass Murder Precipitants and Motivations of Offenders. International Journal of Offender Therapy and Comparative Criminology. 2018; 62(2):427-49.

Meloy JR, Hempel AG, Mohandie K, Shiva AA, Gray BT. Offender and offense characteristics of a nonrandom sample of adolescent mass murderers. Journal of the American Academy of Child & Adolescent Psychiatry 2001;40:719-28.

Follman M, Aronsen G, Pan D. (2012). A guide to mass shootings in America. Mother Jones 2012;15:119. Disponível em:

Adler L, Marx D, Apel H, Wolfersdorf M, Hajak G. Zur Stabilität des 'Amokläufer' - Syndroms. Fortschritte der Neurologie-Psychiatrie. 2006;74:582-90.

Fox JA, Levin J. Mass confusion concerning mass murder. The Criminologist 2015;40(1):8-11.

Petee TA, Padgett KG, York TS. Debunking the Stereotype: An Examination of Mass Murder in Public Places. Homicide studies 1997;1(4):317-37.

Hilal SM, Densley JA, Li SD, Ma Y. The Routine of Mass Murder in China. Homicide Studies. 2014;18(1):83-104.

Agnich LE. A Comparative Analysis of Attempted and Completed School-Based Mass Murder Attacks. American Journal of Criminal Justice. 2014;40(1):1-22.

Nexo. (2019). O que diz a ciência sobre acesso a armas e violência, em 5 estudos. [publicação online]. 2019 [acesso em 10 mar. 2021]. Disponível em

Joslyn MR, Haider-Markel DP. Gun Ownership and Self-Serving Attributions for Mass Shooting Tragedies. Social Science Quarterly. 2017;98(2):429-42.

Heider F. The psychology of interpersonal relations. John Wiley & Sons 1958.

Ferreira MPM. Teoria(s) da atribuição: um quadro explicativo para o rendimento acadêmico. Revista Brasileira de Educação. 2019;24:e240037.

Kleck G. The Impact of Gun Ownership Rates on Crime Rates: A Methodological Review of the Evidence. Journal of Criminal Justice. 2015;43(1):40-8.

Moorhouse JC, Wanner B. (2006). Does Gun Control Reduce Crime or Does Crime Increase Gun Control? Cato Journal. 2006;26(1):103-24.

Lewis JS The Relationship between Gun Control Strictnessand Mass Murder in the United States: A NationalStudy 2009-2015. International Social Science Review 2018;94(2):1-23.

Chapman S, Alpers P, Agho K, Jones M. (2006). Australia's 1996 Gun Law Reforms: Faster Falls in Firearm Deaths, Firearm Suicides, and a Decade without Mass Shootings. Injury Prevention. 2006;12(6):365-72.

Lemieux F. Effect of Gun Culture and Firearm Laws on Gun Violence and Mass Shootings in the United States: A Multi-level Quantitative Analysis. International Journal of Criminal Justice Sciences. 2014;9(1):74-93.

Silva RM. Da Navalha de Occam a um método de categorização de textos simples, eficiente e robusto [Dissertação de Doutorado]. Campinas: Universidade Estadual de Campinas, UNICAMPI; 2017.

Ronel N. Why victimology should stay positive: The ongoing need for positive victimology. Temida. 2015;18:3-6.

Auxemery Y. The mass murderer history: modern classifications, sociodemographic and psychopathological characteristics, suicidal dimensions, and media contagion of mass murders.Compr Psychiatry. 2015;56:149-54.

Levin J, Madfis E. Mass Murder at School and Cumulative Strain. American Behavioral Scientist. 2009;52(9):1227-45.

Hagan CR, Podlogar MC, Joiner TE. Murder-suicide: bridging the gap between mass murder, amok, and suicide. Journal of Aggression, Conflict and Peace Research. 2015;7(3):179-86.

Waiselfisz JJ. Mapa da violência 2014: os jovens do Brasil. Brasília: Flacso; 2014. 185 p.

Moreira LCO, Bastos PRHO. Prevalência e fatores associados à ideação suicida na adolescência: revisão de literatura. Revista Quadrimestral da Associação Brasileira de Psicologia Escolar e Educacional. 2015;19(3): 445-53.

Carretta C, Burgess A, Welner M. Gaps in Crisis Mental Health: Suicide and Homicide-suicide. Archives of Psychiatric Nursing. 2015;29(5):339-45.

Paloski LP, Christ HD. Terapia cognitivo-comportamental para depressão com sintomas psicóticos: Uma revisão teórica. Contextos Clínicos. 2014;7(2):220-8.

Lester D, Stack S, Schmidtke A, Schaller S, Muller I. The deadliness of mass murderers. Psychological Report. 2004;94(3 Pt 2):1404.

Kon Y. Amok. British Journal of Psychiatry. 1994;165(5):658-89.

Kalish R, Kimmel M. Suicide by mass murder: Masculinity, aggrieved entitlement, and rampage school shootings. Health Sociology Review. 2010;19(4):451-64.

Correia E, Lucas S, Lamia A. Profiling: Uma técnica auxiliar de investigação criminal. Análise Psicológica 2007;25(4):595-601.

Lankford A. Race and mass murder in the United States: A social and behavioral analysis. Current Sociology. 2015;64(3):470-90.

Lee JK. (2018). Mass Shootings and Media Contagion Theory: Social Media's Influence on Frequency of Incidents. Elon Journal of Undergraduate Research in Communications. 2018;9(2):27-35.

Shermer M. The Sandy Hook Effect. Skeptic 2013;18(1):33-43. Disponível em:

Dicionário On Line. [publicação online]. [acesso em 10 mar. 2021]. Disponível em

Declerq F, Audenaert K. (2011). A case of mass murder: Personality disorder, psychopathology and violence mode. Agression and violent behavior 2011;16(2):135-43.

Joaquim RM, Radis, LB. (2020). Personalidade e expressão facial da emoção: investigando padrões em um caso de assassinato em massa. Debates em Psiquiatria. 2020;33-42.



How to Cite

Lemos Vasconcelos, S. J., dos Santos Welter, L., Pereira Barbosa, T., Macedo Pinto, L. V., Valli Santanna, R., Portella Quevedo, E., & de Vargas, F. (2021). Mass Murder: An Understanding of Its Causes and Prevention. Brazilian Journal of Forensic Sciences, Medical Law and Bioethics, 10(3), 401–422.