Introduction
In 2021, approximately 48,000 lives were lost to suicide in the United States. During this time, suicide was among the 10 leading causes of death among persons aged 10–64 years and the second leading cause of death among children and adolescents aged 10–14 and adults aged 25–34 years. Suicide rates peaked in 2018, followed by two consecutive years of declines (5%) during COVID-19; during 2020–2021, rates nearly rebounded to the 2018 peak . Age-adjusted rates increased approximately 36% from 10.4 suicides per 100,000 population in 2000 to 14.1 in 2021. Many more persons think about or attempt suicide. In 2021, a total of 12.3 million U.S. adults reported serious thoughts of suicide, 1.7 million attempted suicide, 22% of high school students seriously considered suicide, and 10% attempted suicide. When a group of suicides or suicide attempts occur closer together in time, space, or both than would normally be expected in a community, they are defined as a suicide cluster. Suicide clusters are rare and are believed to comprise only a small proportion of overall deaths by suicide; for example, in the United States, an estimated 1%–2% of teenage suicides are part of clusters. However, suicide clusters can have unique characteristics and challenges and, when they occur, are often highly publicized and can have considerable negative effects on the community, including prolonged grief and elevated fear and anxiety about further deaths.
Overview and Types of Suicide Clusters
Suicide clusters have been reported in diverse populations and settings including psychiatric inpatients , teenagers and young adults, schools, prison inmates, and American Indian and Native American communities. The two most commonly reported types of suicide clusters are point clusters and mass clusters. Point clusters (or spatial-temporal clusters) represent a greater-than-expected number of suicides or suicide attempts that occur within a time period in a specific location (https:// www.cdc.gov/suicide/resources/suicide-clusters.html). Point clusters might occur in a community/county or an institution such as a school, university, or psychiatric inpatient setting.