Review
Clustering of suicides in children and adolescents

https://doi.org/10.1016/S2352-4642(19)30335-9Get rights and content

Summary

Suicide is one of the major causes of death in young people, in whom suicide can occur in clusters. In this Review, we have investigated definitions and epidemiology of such clusters, the factors associated with them, mechanisms by which they occur, and means of intervening and preventing them. Clustering of suicidal behaviour is more common in young people (<25 years) than adults. Suicide clusters can occur as a greater number of episodes than expected at a specific location, including in institutions (eg, schools, universities, psychiatric units, and youth offender units). They might also involve linked episodes spread out geographically. Locations exposed to clusters can be at risk for future clusters. Mechanisms involved in clusters include social transmission (particularly via person-to-person transmission and the media), perception that suicidal behaviour is widespread, susceptible young people being likely to socialise with others at risk of suicidal behaviour, and social cohesion contributing to the diffusion of ideas and attitudes. The internet and social media might have particularly important roles in spreading suicidal behaviour. The effect of suicide clusters on communities and institutions is usually profound. Experience of intervening in clusters has resulted in best practice guidance. This guidance includes preparation for occurrence of clusters in both community and institutional settings. Identification of clusters in the community requires real-time monitoring of suicidal behaviour. Effective intervention is more likely if a cluster response group is established than if no such group exists. The response should include bereavement support, provision of help for susceptible individuals, proactive engagement with media interest, and population-based approaches to support and prevention. Social media can provide a powerful means for disseminating information and reaching young people at risk.

Introduction

Suicide is a leading cause of death in young people aged 25 years and under.1 According to the Global Burden of Disease Study,2 in 2013 suicide accounted for 8·4% of deaths in 15–19-year-olds worldwide. Although suicide occurs more frequently in young males than young females, suicide was the most common cause of death in females aged 15–19 years and the third most common cause in males in the same age group.2 The incidence of suicide increases sharply during adolescence.3 Adolescents have been shown to be particularly susceptible to the phenomenon through which knowledge of the suicide of other adolescents might increase risk of further suicides and, according to a report from 1990, are two to four times more likely than adults to be involved in a suicide cluster.4 Suicide clusters have been documented in individuals as young as 10 years.5 Although relatively uncommon, suicide clusters generate considerable concern in the communities in which they occur. This concern is especially marked when a cluster occurs in a single school or university. The trauma associated with the suicide of a young person and increasing awareness of suicide clusters can lead to widespread fear and anxiety, as well as prolonged grief.6, 7, 8

Self-harm, defined as intentional non-fatal self-injury or self-poisoning irrespective of degree of suicidal intent or other type of motive,9 can also occur in clusters, these clusters being relatively common in young people, as found in an early national study of attempted suicide in New Zealand,10 and in subsequent investigations.11 Such clusters occur particularly in institutional settings such as schools and psychiatric units.5 Self-harm is a key factor associated with suicide in young people.12 Therefore, clusters can include both suicide and self-harm;11 indeed, linked episodes of self-harm might be a precursor to a suicide cluster.13

We have reviewed the research and clinical literature on suicide clusters in young people. Evidence regarding the prevalence of clusters of suicidal behaviour is presented, followed by what is known about the risk factors associated with susceptibility of youngsters to being involved in them and also possible underlying mechanisms. Finally, we consider interventions for the management and prevention of suicide clusters in young people. In this Review the term young people refers to children, adolescents, and young people between ages 10–24 years. This broader view of adolescence has important implications for cluster prevention, particularly in environments such as universities and custodial settings, whose populations of young people aged 18–24 years are otherwise excluded from a narrow conceptualisation of adolescence.14 Furthermore, studies of clustering phenomena often include young adults with children and adolescents.

Key messages

  • Suicide clusters occur more frequently in young people than in adults

  • They can occur as a larger number of episodes than expected at a specific location, including in institutions such as schools, universities, psychiatric units, and young offender units, or as linked episodes spread out geographically that occur over a relatively short period of time

  • The effect of suicidal clusters on communities and institutions is usually profound and associated with a sense of panic

  • Some of the mechanisms involved in clusters include social transmission (particularly via person-to-person transmission and the media), perceptions that suicidal behaviour is widespread, assortative relating whereby susceptible young people are more likely to socialise with others at risk than other young people, and social cohesion contributing to the spread of ideas and attitudes

  • The internet and social media might have particularly important roles in spreading information about suicidal behaviour, which might facilitate its occurrence

  • Responding to an apparent cluster should include bereavement support, provision of help for susceptible individuals, engaging with the media proactively, and population approaches to support and prevention

  • Social media and the internet can provide powerful means for disseminating helpful information (including tools to support those who self-harm), reaching young people at risk, and encouraging susceptible youth to seek help

Section snippets

Definition, epidemiology, and risk of suicide clusters

The term suicide cluster describes a situation in which more suicides than expected occur in terms of time, place, or both. Varying definitions of such clusters have been proposed,5 reflecting the absence of a specific agreed definition of the phenomenon. A suicide cluster usually includes three or more deaths; however, two suicides occurring in young people in a specific community or setting (eg, a school, university, or inpatient psychiatric unit), in a short time period, should also be taken

Mechanisms that might explain the occurrence of suicide clusters

Several factors and mechanisms have been suggested to explain the occurrence of point clusters (table). These mechanisms are not mutually exclusive and might act in concert, to varying degrees, for different point clusters. However, a few empirical studies focusing on point clusters that explicitly contribute to our understanding of these mechanisms exist.16

Social transmission postulates that a causal effect of exposure exists, either via indirect exposure through the media or direct exposure

Internet, social media, and other new media influences in suicide clusters

Concern regarding the influence of the internet, social media, and other new media (eg, online streaming of films and suicidal acts) on self-harm and suicidal behaviours has grown in the past few years alongside their increased use, particularly in young people. Systematic reviews have identified substantial potential for harm from online activity in relation to suicidal behaviours (eg, normalisation, triggering, competition, and cyberbullying), but also the potential for benefits (eg, crisis

Identifying and responding to a suicide cluster

Suicide can devastate families, friends, work colleagues, teachers, and others. Any suicide usually affects many people and the aftermath of suicides of young people can be particularly profound.65 Because people bereaved by suicide themselves have an increased risk of suicide,65 this elevated risk might add to the possible extension of a suicide cluster. Awareness of a suicide cluster in a community or institution can cause panic, and sometimes uncoordinated efforts to introduce interventions

Conclusions

How suicide can cluster in young people in community and institutional settings is increasingly recognised. The mechanisms involved might include direct exposure to the behaviour, media reporting, belief that the behaviour is commonplace, susceptible individuals sharing social groups, and influence of social media and the internet. Once occurrence of a cluster is suspected, a carefully coordinated and preferably pre-planned response should take place, ideally by an identified cluster response

Search strategy and selection criteria

We searched the following databases from inception to December, 2017: PsycINFO, Web of Knowledge, Medline, ASSIA, Sociological Abstracts, IBSS, and Social Services Abstracts, using the following search terms: “suicid*”, “self-harm”, “self-injur*”,“self-mutilat*” AND “cluster*”, “space-time”, “echo”, “spatial”, “geospatial”, “mass”, “media” OR “imitat*”,“epidemic”,“copycat”, “modelling”, “werther effect”, “priming”, “assort*”, “learning”, “prestige bias”, “homophil*”, “similarity bias”,

References (73)

  • A Pitman et al.

    Effects of suicide bereavement on mental health and suicide risk

    Lancet Psychiatry

    (2014)
  • Preventing suicide: a global imperative

    (2014)
  • MS Gould et al.

    Suicide clusters: an examination of age-specific effects

    Am J Public Health

    (1990)
  • C Niedzwiedz et al.

    The definition and epidemiology of clusters of suicidal behavior: a systematic review

    Suicide Life Threat Behav

    (2014)
  • Centres for Disease Control. Cluster of suicides and suicide attempts. New Jersey,...
  • CJ Heffel et al.

    The aftermath of a suicide cluster in the age of online social networking: A qualitative analysis of adolescent grief reactions

    Contemp Sch Psychol

    (2015)
  • L Robertson et al.

    An adolescent suicide cluster and the possible role of electronic communication technology

    Crisis

    (2012)
  • Self-harm in over 8s: long-term management

  • MS Gould et al.

    Clustering of attempted suicide: new Zealand national data

    Int J Epidemiol

    (1994)
  • LS Too et al.

    Clusters of suicides and suicide attempts: detection, proximity and correlates

    Epidemiol Psychiatr Sci

    (2017)
  • K Hawton et al.

    Repetition of self-harm and suicide following self-harm in children and adolescents: findings from the multicentre study of self-harm in England

    J Child Psychol Psychiatry

    (2012)
  • K Hacker et al.

    Coping with youth suicide and overdose: one community's efforts to investigate, intervene, and prevent suicide contagion

    Crisis

    (2008)
  • J Callahan

    Negative effects of a school suicide postvention program—a case example

    Crisis

    (1996)
  • C Haw et al.

    Suicide clusters: a review of risk factors and mechanisms

    Suicide Life Threat Behav

    (2013)
  • P Jones et al.

    Identifying probable suicide clusters in wales using national mortality data

    PLoS One

    (2013)
  • A Marchant et al.

    A systematic review of the relationship between internet use, self-harm and suicidal behaviour in young people: the good, the bad and the unknown

    PLoS One

    (2017)
  • J Robinson et al.

    Spatial suicide clusters in Australia between 2010 and 2012: a comparison of cluster and non-cluster among young people and adults

    BMC Psychiatry

    (2016)
  • DP Phillips et al.

    Clustering of teenage suicides after television news stories about suicide

    N Engl J Med

    (1986)
  • T Niederkrotenthaler et al.

    Association of increased youth suicides in the united states with the release of 13 reasons why

    JAMA Psychiatry

    (2019)
  • G Larkin et al.

    Geospatial mapping of suicide clusters

  • LS Too et al.

    Clusters of suicidal events among young people: do clusters from one time period predict later clusters?

    Suicide Life Threat Behav

    (2019)
  • GR Cox et al.

    Suicide clusters in young people: evidence for the effectiveness of postvention strategies

    Crisis

    (2012)
  • KA Fowler et al.

    Epidemiological investigation of a youth suicide cluster: Delaware 2012

    Del Med J

    (2013)
  • C Wilkie et al.

    Community case study: suicide cluster in a small Manitoba community

    Can J Psychiatry

    (1998)
  • DW Bechtold

    Cluster suicide in American Indian adolescents

    Am Indian Alsk Native Ment Health Res

    (1988)
  • YT Cheung et al.

    Application of scan statistics to detect suicide clusters in Australia

    PLoS One

    (2013)
  • Cited by (76)

    • Conversational agents for depression screening: A systematic review

      2024, International Journal of Medical Informatics
    View all citing articles on Scopus
    View full text