Prevalence of exposure to suicide: A meta-analysis of population-based studies

Highlights

• Exposure to suicide is a risk factor for adverse mental health and suicidal behavior.

• 4.3% and 22% of the population have been exposed to a suicide during the past year and their lifetime respectively.

• Exposure to suicide among friends and peers, and in all relationships, is higher than exposure in the family.

• Suicide bereavement research and support should go well beyond the family context.

• Standardised assessment methods and well-designed studies are needed.

Abstract

Those exposed to suicide are at increased risk of adverse outcomes including mental illness, impaired social functioning, and fatal and non-fatal suicidal behavior. However, it is unclear how many people are exposed to suicide in the general community. This first meta-analysis of population-based studies aimed to provide pooled estimates of past-year and lifetime prevalence of exposure to suicide among family, friends/peers, and all relationships. In addition, the study examined prevalence of exposure to suicide by age group: adolescents and adults. Systematic searches of the literature in Embase, Medline and PsycINFO identified eighteen studies that were included in the analysis. Pooled past-year prevalence was 4.31% (CI: 2.50 to 6.58) and life-time prevalence 21.83% (CI: 16.32 to 27.90). Both past-year and lifetime prevalences of exposure to suicide among friends and peers were significantly higher than the prevalence of exposure within families; there were no differences in the prevalence of exposure to suicide between adolescents and adults. Heterogeneity was highly significant. Future research should be conducted with large national representative samples and use standardised assessment instruments. Given the increased risks of adverse outcomes among those exposed to suicide, the high rate of exposure to suicide reported here has important ramifications for public health and mental health service delivery.

Introduction

Suicide is a major public health problem with 42,773 registered suicides (13.4/100,000 inhabitants) in the US in 2014 (Drapeau and McIntosh, 2015), and an estimated 804,000 suicides (11.4/100,000) worldwide in 2012 (World Health Organization, 2014). Those bereaved by suicide are at risk for a range of adverse outcomes including grief reactions, mental illness and impaired social functioning (Bolton et al., 2013, Pitman et al., 2014, Sveen and Walby, 2008, Wilcox et al., 2015). Importantly, exposure to suicide is also a risk factor for fatal and non-fatal suicidal behavior (De Leo and Heller, 2008, O'Connor and Nock, 2014, Turecki and Brent, 2016). There is strong evidence of aggregation of suicide risk in families exposed to suicide (Qin et al., 2002, Tidemalm et al., 2011), as well as evidence of increased suicide risk after exposure to suicide of non-family members among adolescents (Andriessen et al., 2016) and adults (Hedström et al., 2008, Maple et al., 2016). Kinship, time since loss, personal and family mental health history, and pre-loss life events (such as separations) may affect the impact of the suicide death (Jordan and McIntosh, 2011, Pitman et al., 2014). The impact of suicide is stronger when experienced during childhood and adolescence, compared to other age groups (Andriessen et al., 2016, Wilcox et al., 2010) and compared to natural causes of death (Berg et al., 2016).

Support for those bereaved by suicide (i.e., the survivors) is an important strategy for suicide prevention (U.S. Department of Health and Human Services, 2012, World Health Organization, 2014). However, it is still unclear how many people are exposed to a suicide death, and potentially in need of support. Although there is no consensus definition of who constitutes a ‘survivor’ (Andriessen and Krysinska, 2012, Cerel et al., 2014), the literature describes a survivor as a self-defined condition of a person who has been exposed to a suicide, and feels affected by the death (Andriessen, 2009, Jordan and McIntosh, 2011). For our study, exposure to suicide was defined as having experienced a suicide among family or friends, or having personally known someone who has died through suicide.

A number of studies have estimated the average number of survivors after a single suicide. Shneidman (1969, p. 22) originally postulated an average of a “half-dozen” survivors per suicide. While this ‘educated guess’ has been perpetuated in the literature, other authors have estimated higher numbers. Berman (2011) conducted a survey among the members of the ‘Survivor Division’ of the American Association of Suicidology. Along with a number of sociodemographic variables, respondents were asked to estimate the number of persons directly affected by the suicide death that they had experienced. The study found that the estimated numbers of survivors varied depending on kinship and age: parents bereaved by child suicide estimated that there were 80 survivors (“deeply affected”, Berman, 2011, p. 111), partners and spouses estimated the number of survivors as 60, and siblings and friends indicated between 45 and 50 survivors. For all respondents, the study estimated an average of five (5.13) immediate family members bereaved by a single suicide. Also, studies based on population registers from different countries have calculated the number of survivors per suicide for selected types of relationship. Kuramoto et al. (2010) and Wilcox et al. (2010) found that on average two children (1.7–1.9) are bereaved after the suicide of a parent. Hedström et al., 2008, Botha et al., 2009 and Chen et al. (2009) estimated an average of three (2.9), four (3.7) and five relatives bereaved by a suicide in the family, respectively.

Other studies have calculated the prevalence of exposure to suicide for selected types of relationship based on population registers. Agerbo et al. (2002) and Mittendorfer-Rutz et al. (2008) reported a lifetime experience of 0.56% and 0.25% of father and mother suicides respectively, and Chen et al. (2009) found that 2.31%–2.71% of Japanese people were bereaved by the suicide of a family member.

To the best of our knowledge, to date no meta-analysis has been published on the prevalence of exposure to a death by suicide, i.e. having experienced a suicide among family or friends, or having personally known someone who has died through suicide. This study aimed to redress this gap in knowledge by examining general population studies, and quantifying reported prevalences of people exposed to suicide. The study examined past-year and lifetime prevalence of exposure to suicide, and considered exposure among family, friends/peers, and all relationships. In addition, the study investigated exposure to suicide by age group: i.e. adolescents and adults. We also included location of the studies (by country) and number of questions asked about exposure to suicide as potential confounding factors.