1 INTRODUCTION

Suicide is a global mental health problem for people of all ages, accounting for 800 000 deaths each year (World Health Organization, 2019b). In 2016, the global age-standardized suicide rate was 10.5 per 100 000 population, showing a 9.8% decrease since 2010 (World Health Organization, 2019a). Overall suicide rates also decreased in South-East Asia (13.4 per 100 000, −4.2%) and in the Western Pacific Region (8.4 per 100 000, −19.6%). The global age-standardized suicide rate has been estimated to be 1.8 times higher in males than in females. Nevertheless, there are countries such as Bangladesh (6.7 vs. 5.5), China (8.3 vs. 7.9), and Myanmar (9.8 vs. 6.3) where the suicide rates are higher among females. Furthermore, the female age-standardized suicide rate in South-East Asia region is far higher than the global female average (11.5 vs. 7.5 per 100 000).

Suicide rates are lowest in the youngest age groups (under 15 years of age) and highest in those aged 70 years or older (World Health Organization, 2014). Nevertheless, significant numbers of children and adolescents die from suicide. More than 60 000 children and adolescents aged 10–19 across the world took their lives in 2016. Suicide represents the third leading cause of death in 15–19-year-olds, after road injury and interpersonal violence (World Health Organization, 2019a).

The World Health Organization (2013) has recognized suicide prevention as a major public health priority and advocated for the development and implementation of comprehensive national strategies, taking into special consideration youth and other vulnerable groups. Furthermore, the current global crisis generated by the COVID-19 pandemic is raising concerns about the risk for increased suicide rates all over the world (Gunnell et al., 2020; Holmes et al., 2020; D. Wasserman et al., 2020). Even if children are clinically less affected by COVID-19, they are over-exposed to the indirect effects of the pandemic, such as separations, losses, disruption of school and social and health services (Clark et al., 2020; Lee, 2020). Preliminary reports have already shown a surge in incidence of attempted and completed suicide among children and adolescents in England and South Asia (Ingram, 2020; Odd et al., 2020). For this reason, the implementation of evidence-based suicide preventive strategies is much needed. Strategies need to be adapted to the current context that is imposing restrictions on in-person interventions and is characterized by limited healthcare and economic resources.

2 METHODS

The current paper used a narrative review method to summarize current knowledge about risk and protective factors for suicide among children and adolescents and to discuss evidence-based strategy for suicide prevention in this age group. The stress vulnerability model of suicidal behavior (Mann & Arango, 1992; D. Wasserman & Sokolowski, 2016) and the Universal-Selective-Indicated model for suicide prevention (Institute of Medicine (US) Committee on Pathophysiology and Prevention of Adolescent and Adult Suicide, 2002; D. Wasserman & Durkee, 2009) provide a theoretical framework.

Literature searches were conducted, using PubMed and Google Scholar, in order to identify studies assessing the role of different risk and protective factors, as well as those assessing the effectiveness of suicide prevention strategies among children and adolescents. Articles were included in the narrative review if they were published in English language peer-reviewed journals and discussed cross-sectional, cohort, case–control or interventional studies. When available, data coming from large international surveys, systematic-review, and meta-analyses were favored.

2.1 Epidemiology of suicide and suicidal behavior among children and adolescents

In almost all regions of the world, the rate of death from suicide in youth under 14 years of age is approximately 0.6 per 100 000 (Dervic et al., 2008) and suicide in childhood and early adolescence is considered to be uncommon. There are few studies only, most of them conducted in developed countries that investigate suicide in this age group (Dervic et al., 2008; Soole et al., 2015). The occurrence of suicide is likely to be underestimated in these reports because of reluctance of coroners to assign the cause of death in the death certificates (Hawton & James, 2005).

Recently, Glenn et al. (2020) calculated a pooled suicide rate of 3.77 per 100 000 for children and youth aged 10–19 years. Suicide rates increase during adolescence, reaching a rate of 6.04 per 100 000 in 15–19 years teenagers (vs. 0.93 per 100 000 in 10- to 14-year-olds). A stabilization or a decrease of adolescent suicide rates has been described across much of the world (Kolves & De Leo, 2016; McLoughlin et al., 2015). However, South America and East Asia show the opposite trend (Kolves & De Leo, 2016).

Rates for 15–19 years old boys are more than twice those for girls (8.41 vs. 2.98 per 100 000). This gender disparity is more evident in late adolescence (0.76 vs. 0.64 per 100 000) (Glenn et al., 2020).

During childhood, suicidal ideation is rare. It slowly increases in frequency until adolescence and then shows a sharp increase up to young adulthood (Borges et al., 2012). Several studies show that almost 30% of the adolescents participating had thought about suicide and 4.2%–17% report attempted suicide at some point in their lives (Carli et al., 2014; Evans et al., 2005; Kokkevi et al., 2012; Nock et al., 2013; Uddin et al., 2019) (Table 1).

TABLE 1. Prevalence of suicidal ideation and suicide attempts in different studies Study Country/region Sample Suicidal ideation Suicide attempt

Carli et al., 2014

SEYLE

(Saving and Empowering Young Lives in Europe)

11 European countries

12 395 high school students

Mean age = 14.91 ± 60.90

Prevalence (positive on at least one item of the Paykel Suicide Scale) = 32.3% Lifetime prevalence = 4.2%

Kokkevi et al., 2012

ESPAD

(European School Survey Project on Alcohol and Other Drugs)

17 European countries

45 806 high school students

Age: 15–16 years

Median prevalence of frequent self-harm thoughts = 7.4% (range 2.1%–15.3%) Median prevalence of any lifetime self-reported suicide attempt = 10.5% (range 4.1%–23.5%)

Nock et al., 2013

National Comorbidity Survey Replication Adolescent Supplement

US

6483 adolescents (household and school subsamples)

Age: 13–18 years

Lifetime prevalence (serious thoughts about killing themselves) = 12.1% Lifetime prevalence = 4.1%

Uddin et al., 2019

Global School-based Student Health Survey

59 low-income and middle-income countries

229 129 students

Mean age: 14.6 ± 1.18

12-month prevalence (seriously considering suicide) = 16.9% 12-month prevalence = 17%

Suicide ideation and prior attempts represent major risk factors for suicide in children (Soole et al., 2015) and adolescents (McLoughlin et al., 2015). Hulten et al. (2001) reported that around one fourth of European adolescent who attempted suicide made another attempt within the following year. Nock et al. (2013) described the transition from suicide ideation to attempt as happening generally within the first year after onset. They estimated that approximately one-third of adolescents with suicide ideation go on to develop a suicide plan and approximately 60% of those with a plan attempt suicide.

Even if males are more likely to die by suicide, suicide ideation and attempts occur more often among females. This is described as the gender paradox in suicidal behavior (Canetto & Sakinofsky, 1998), attributable in part to differences in preferred suicide means. Males tend to choose more lethal methods (e.g., hanging and firearms) than those chosen by females (e.g., self-poisoning) (Varnik et al., 2008). There are also consistent reports of a higher prevalence of suicidal thoughts and attempts among girls compared with boys (Carli et al., 2014; Evans et al., 2005; Kokkevi et al., 2012; Nock et al., 2013; Uddin et al., 2019).

Considering the South East Asia and Western Pacific regions (Tables 2 and 3), crude suicide rates in young people aged 10–19 years vary from less than 1 or 2 per 100 000 (Brunei Darussalam, Fiji, Maldives, Vietnam, China, Malaysia) to approximately 11–16 per 100 000 (Micronesia, India, New Zealand, Kiribati). These four countries are among the 10 with the highest suicide rates in this age group worldwide (World Health Organization, 2020).

TABLE 2. Suicide rates of the WHO South East Asia region (year 2016) Country Age-standardized suicide rate, all ages (per 100 000) Crude suicide rates, all ages (per 100 000) Crude suicide rates, 10–19 years old (per 100 000) Bangladesh Both sexes 6.1 5.9 6.2 Females 6.7 7.0 9.8 Males 5.5 4.7 2.7 Bhutan Both sexes 11.6 11.4 4.9 Females 8.9 8.5 4.6 Males 13.8 14.0 5.2 India Both sexes 16.5 16.3 11.2 Females 14.5 14.7 15.0 Males 18.5 17.8 7.8 Indonesia Both sexes 3.7 3.4 2.0 Females 2.2 2.0 1.3 Males 5.2 4.8 2.7 Maldives Both sexes 2.7 2.3 1.2 Females 1.6 1.3 1.4 Males 3.6 3.0 1.0 Myanmar Both sexes 8.1 7.8 4.7 Females 9.8 9.5 6.2 Males 6.3 5.9 3.3 Nepal Both sexes 9.6 8.8 6.0 Females 8.0 7.9 7.0 Males 11.4 9.7 5.0 Sri Lanka Both sexes 14.2 14.6 6.2 Females 6.2 6.4 6.2 Males 23.3 23.5 6.2 Thailand Both sexes 12.9 14.4 5.6 Females 4.8 5.9 1.8 Males 21.4 23.4 9.2 Timor-Leste Both sexes 6.4 4.6 3.0 Females 3.7 2.9 3.3 Males 9.0 6.2 2.8 Note: Sources: World Health Organization. (2019). Suicide in the world: global health estimates; World Health Organization, Global Health Observatory (www.who.int/data/gho). TABLE 3. Suicide rates of the WHO Western Pacific region (year 2016) Country Age-standardized suicide rate, all ages (per 100 000) Crude suicide rates, all ages (per 100 000) Crude suicide rates, 10–19 years old (per 100 000) Australia Both sexes 11.7 13.2 5.6 Females 6.0 7.0 3.9 Males 17.4 19.5 7.3 Brunei Darussalam Both sexes 4.5 4.6 0.6 Females 2.8 2.7 0.4 Males 6.2 6.4 0.7 Cambodia Both sexes 5.9 5.3 2.4 Females 3.2 2.9 1.6 Males 9.0 7.8 3.1 China Both sexes 8.0 9.7 1.9 Females 8.3 10.3 2.3 Males 7.9 9.1 1.5 Fiji Both sexes 5.5 5.0 1.2 Females 2.5 2.4 1.5 Males 8.8 7.5 0.9 Japan Both sexes 14.3 18.5 4.8 Females 8.1 11.4 3.0 Males 20.5 26.0 6.6 Kiribati Both sexes 15.2 14.4 16 Females 5.4 5.0 7.3 Males 25.9 24.1 24.2 Laos People's Democratic Republic Both sexes 9.3 8.6 6.3 Females 6.1 5.7 4.8 Males 12.9 11.4 7.8 Malaysia Both sexes 6.2 5.5 1.9 Females 3.6 3.2 0.9 Males 8.7 7.8 2.9 Micronesia (Federated States of) Both sexes 11.3 11.1 10.8 Females 6.2 6.3 7.8 Males 16.2 15.8 13.6 Mongolia Both sexes 13.3 13.0 6.9 Females 3.8 3.5 3.1 Males 23.3 22.6 10.7 New Zealand Both sexes 11.6 12.1 11.2 Females 6.2 6.6 8.1 Males 17.3 17.9 14.2 Papua New Guinea Both sexes 7.0 6.0 5.2 Females 3.8 3.3 3.8 Males 10.2 8.6 6.5 Philippines Both sexes 3.7 3.2 2.5 Females 2.3 2.0 2.1 Males 5.2 4.3 2.9 Republic of Korea Both sexes 20.2 26.9 4.4 Females 11.6 15.4 3.9 Males 29.6 38.4 4.9 Samoa Both sexes 5.4 4.4 2.6 Females 2.2 1.9 1.6 Males 8.7 6.7 3.6 Singapore Both sexes 7.9 9.9 3.7 Females 4.9 6.1 3.3 Males 11.1 13.8 4.0 Solomon Islands Both sexes 5.9 4.7 4.7 Females 3.2 2.6 3.2 Males 8.5 6.8 6.0 Tonga Both sexes 4.0 3.5 2.5 Females 2.9 2.7 2.3 Males 5.2 4.3 2.6 Vanuatu Both sexes 5.4 4.5 4.4 Females 2.7 2.2 2.6 Males 8.1 6.6 6.0 Vietnam Both sexes 7.0 7.3 1.8 Females 3.4 3.7 1.0 Males 10.8 10.9 2.5 Note: Sources: World Health Organization. (2019). Suicide in the world: global health estimates; World Health Organization, Global Health Observatory (www.who.int/data/gho).

While the suicide rate among children and adolescents is lower than that in the general population globally, in several countries (Bangladesh, Kiribati, Micronesia, New Zealand), there is no such discrepancy. When considering females only, the suicide rates among youth are higher than that in the general population in many countries (Kiribati, Micronesia, New Zealand, Papua New Guinea, Philippines, Solomon Islands, Vanuatu). Furthermore, there are several countries in which the suicide rate for girls exceeds that for boys (Bangladesh, India, China, Fiji, Maldives, Myanmar, Nepal, Timor Leste). India has the highest suicide rate among 10–19 year old females (15 per 100 000), which is almost twice the rate among males in the same age group (7.8 per 100 000). The gender disparity is particularly marked in Bangladesh, where the suicide rate among girls is more than triple that in boys (9.8 vs. 2.7 per 100 000).

Uddin et al. (2019) used the data of the data of the Global School-based Student Health Surveys to estimate the prevalence of suicide ideation among 13–17 years old students in 59 low- and middle-income countries. The 12-month prevalence was lowest in South East Asia (suicidal ideation: 8%, suicide planning: 9.9%, suicide attempts: 9.2%) and highest in the Western Pacific countries (suicidal ideation: 17.9%, suicide planning: 17.7%, suicide attempts: 20.5%). The high prevalence of bullying victimization and physical fights, as well as the intergenerational conflicts and family pressures deriving from societal transition in countries with fast-growing populations have been hypothesized to contribute to the disproportionate prevalence of suicide attempts in the Western Pacific region. In a meta-analysis of 43 studies on Chinese adolescents, the prevalence of suicide attempts ranged from 0.94% to 9.01%, with a pooled prevalence of 2.94% (Hu et al., 2015). As for global figures, the prevalence of suicide attempts was higher among girls than boys (3.17% vs. 2.50%).

2.2 Risk and protective factors for suicide among children and adolescents

Suicide is a complex phenomenon influenced by the impact of biological, psychological, social, and environmental factors. The multifaceted interactions of these factors are captured by the stress-diathesis model (Mann & Arango, 1992; D. Wasserman & Sokolowski, 2016), which has been used as framework for this narrative review. In this model, the constitutional predisposition (“trait” or “diathesis”) for suicide is thought to be determined by genetic factors or early life experiences which so define the suicidal threshold. When state-dependent factors (e.g., acute psychiatric conditions, alcohol or substance use or interpersonal and social stressors) intervene, individuals with a low suicide threshold are more likely to act than those with a higher threshold. Although the vulnerability is conceived of as strongly influenced by constitutional and early life factors, changes may still occur. Indeed, suicidal acts are the result of a process of varying length. The process may be as short as a few days only, or else extend over weeks or months, during which risk and protective factors interplay to decrease or enhance the resilience to stress and so alter the suicidal threshold (D. Wasserman, 2016; D. Wasserman & Sokolowski, 2016). The suicidal process is usually short in children and adolescents, related to lack of experience and as well as lack of effective coping styles for tackling impulsivity and aggression in this age group. Similar risk and protective factors have been identified for suicidal behavior in both adults and adolescents, even if they may play a different role at different ages (Brent et al., 1999; O'Neill et al., 2018).

2.3 Genetic and neurobiological factors associated with suicide in youth

Suicide and suicidal behavior cluster in families (Brent & Melhem, 2008; Pedersen & Fiske, 2010; Tidemalm et al.,