Suicide Clusters: A Review of Risk Factors and Mechanisms

Suicide clusters, although uncommon, cause great concern in the communities in which they occur. We searched the world literature on suicide clusters and describe the risk factors and proposed psychological mechanisms underlying the spatio‐temporal clustering of suicides (point clusters). Potential risk factors include male gender, being an adolescent or young adult, drug or alcohol abuse, and past history of self‐harm. However, the majority of studies lack methodological rigor. Many different psychological mechanisms are described, including contagion, imitation, suggestion, learning, and assortative relating, but supporting empirical evidence is generally lacking. More scientifically rigorous studies are needed to improve understanding of suicide clusters.     

The Definition and Epidemiology of Clusters of Suicidal Behavior: A Systematic Review

Suicide clusters are a rare and underresearched phenomenon which attract wide media attention and result in heightened concern in the communities where they occur. We conducted a systematic literature review covering the definition and epidemiology of the time–space clustering of suicidal behavior. Of the 890 articles identified by electronic searching, 82 were selected for inclusion and the extracted data were analyzed by narrative synthesis. Less than a third of studies included a definition of a suicide cluster, and definitions varied considerably. Clusters occurred in various settings, including psychiatric hospitals, schools, prisons, indigenous communities, and among the general population. Most clusters involved young people. The proportion of all episodes that occurred in clusters varied considerably between studies and partly depended on study methodology (e.g., a larger proportion was found in studies of specific clusters compared with general population studies). Future studies should aim to combine the statistical analysis of time–space clustering with a case study of events, which examines potential links between individuals and the wider environmental context.