Suicide is the second leading cause of death in children and adolescents and occurs at a higher rate in this population than in any other age group. In their latest Annual Research Review published in the Journal of Child Psychology and Psychiatry, Christine B. Cha and colleagues outline the epidemiology and potential etiology of suicide, indicate possible therapeutic and preventative strategies and highlight the areas that remain for future research.
Suicide is a global, leading cause of death, but it is most prevalent in adolescents and young adults. A wealth of studies has identified potential risk factors to help explain how and why suicidal behaviours emerge during adolescence. But despite vast progress, a full understanding of the etiology is lacking, thus hindering the development of effective therapeutic and preventative measures.
Cha et al. first note that there is a lack of consistent definitions and classifications throughout the suicide literature. As such, they encourage that sufficient detail be provided when defining study variables in future studies, to avoid misclassification. Cha et al. define suicidal ideation as “the consideration of or desire to end one’s own life”. Such desire may range from passive (wanting to be dead) to active ideation (wanting to kill oneself), and may occur as frequently as once per week. Suicide attempt differs from ideation as with an attempt, an action intended to deliberately end one’s own life is made. Suicide death is defined as “a fatal action to deliberately end one’s own life”, and the method that is used seems to vary geographically.
Epidemiology: The prevalence of suicidal ideation in adolescents ranges from 19.8 to 24.0%, starting after the age of 10 years and rapidly increasing up to age 17 years. Those who experience suicidal ideation during adolescence are ~12 times more likely to attempt suicide by the age of 30 years. Suicide attempts have a lifetime prevalence of 3.1% to 8.8%: they typically occur after the age of 12 years and increase in prevalence in mid-to-late adolescence. Suicide-associated death accounts for 8.5% of all deaths in adolescents and young adults aged 15 to 29 years, and increases in prevalence from ages 15 to 19 years.
The developmental nature of suicide risk across adolescence is under-reported. Interestingly, the timing of puberty has been shown to have an effect on suicidal behaviours, but how or why this is the case is unknown. Cha et al. suggest, therefore, that more longitudinal studies that include wide age ranges and encompass developmental shifts during adolescence would be valuable.
Gender differences can be observed in suicidal behaviour: adolescent girls are more likely to experience suicidal ideation and attempt suicide than boys, yet boys are up to three times more likely to die by suicide. Gender identity and sexual orientation also impacts on the prevalence of suicide ideation and attempt. Adolescents who relate to a sexual minority status show an elevated risk of suicidal behaviours than their heterosexual counterparts. Risk of suicide death is also higher in indigenous American Indian, Alaska Native and Aboriginal youths in the USA and Canada compared to other ethnicities. However, these high-risk socio-demographic populations are under-represented in the suicide literature and thus Cha et al. encourage more attention be paid to these high-risk populations in future studies.
Many risk factors for suicidal behaviours have been described, but a clear understanding of the pathways through which suicidal behaviours develop has not yet been reached. In terms of environmental risk factors, childhood maltreatment/bullying is one of the strongest factors influencing suicidal thoughts and behaviours in adolescents. Twin studies have shown that sexual abuse in childhood can predict future suicidal ideation and suicide attempt. Long periods of exposure to bullying also increase the likelihood of suicidal ideation and attempt, in both the victim and offender. Cyber bullying and the impact of social media is an important consideration in today’s digital revolution, but Cha et al. find that the data thus far are mixed: some have proposed that the Internet provides a forum of help and social support, while others highlight that it can offer sources of suicide-related information.
Psychological factors that correlate with suicidal behaviours have mostly been measured by self-report, behaviour and physiology. The researchers describe that affective processes, such as worthlessness, low self-esteem and negative self-referential thinking, can strongly predict future suicidal ideation and suicide attempt. In terms of cognitive factors that correlate with suicidal behaviours, impulsivity has received moderate support as a risk factor for suicidal behaviour, particularly when in combination with aggression. Others have reported that deficits in sustained attention and vigilance correlate with suicidal thoughts and behaviours. Interpersonal connectedness (loneliness) has been widely assessed in longitudinal studies, but the evidence in support of loneliness as a direct risk factor for suicidal behaviours is only moderate.
Biological correlates: Several biological correlates with suicidal thoughts have been described. For example, researchers identified lower functional connectivity between several neural regions in those who are suicidal compared to controls. Specifically, structural abnormalities have been detected in the hippocampus, dorsolateral prefrontal cortex and highly interconnected brain neural networks involved in regulating the resting brain state.
At the molecular level, serotonin is the most widely studied molecule in terms of suicidal behaviours, with studies dating back to the 1970’s showing low serotonin levels in those who have died by suicide compared to controls. Preliminary studies have also implicated abnormal TNFa, IL-b and BDNF levels in suicidal behaviours. Finally, although preliminary studies support that there is a heritable component to suicidal behaviour, the genetic basis is currently unknown. Cha et al. consider that genetic studies are lacking in this field, in particular genome wide association studies.
Although these biological findings are, on the most part, only preliminary, research in this area is rapidly evolving. Cha et al highlight that the biological factors identified thus far have corroborated behavioural and self-reported data but there remains disconnect between biological mechanisms and overt behaviours. Cross-disciplinary collaborations are required to better link biological and behavioural factors and identify biological targets that can be readily manipulated for intervention.
Cha et al. focus on the psychological interventions to reduce risk of suicide in adolescents, primarily reporting on data from randomized controlled trials. Interventions with the strongest support have a focus on behaviour change, skill-enhancement and strengthening of interpersonal bonds. Individual and family therapy, such as Integrated Cognitive Behavioural Therapy and Attachment-based Family Therapy, are effective in treating adolescents demonstrating suicidal behaviours. Both of these therapies have shown immediate and short-term effects, with a reduced number of suicide attempts after therapy.
Other individual treatments aim to improve a child’s interpersonal skills to decrease risk of suicidal behaviours. One example is dialectical behaviour therapy (DBT) that focuses on strengthening interpersonal effectiveness, mindfulness, distress tolerance and emotion regulation. Another is interpersonal psychotherapy in school settings (IPT-A-IN), which focuses on developmentally appropriate interpersonal problems. Both DBT and IPT-A-IN have shown superiority to controls receiving standard treatment in reducing severity of suicidal ideation, but the data are still preliminary. More research is required to assess the long-term effects of these interventions.
Technology-based interventions (such as smart-phone applications) may be used to create an aversion to death, suicide and self-injury. The results thus far are promising, suggesting that individuals using an app-based intervention reduce engagement in suicidal behaviours in the short term. Cha et al. propose that mobile technology may provide a rich source of real-time data to identify short-term behavioural signatures of suicide risk, as to date, most studies have focused only on long-term follow-ups.
Prevention: The researchers outline three main preventative strategies to reduce the prevalence of suicidal thoughts and behaviours in adolescents. The first strategy is universal prevention, in which entire populations (such as schools) are educated about risk. Data from randomized controlled trials have thus far been positive in reducing self-reported suicide attempts at 3 months post-intervention.
The second preventative strategy is selective prevention. These programs teach adaptive skills, such as problem solving, to pre-empt the development of common risk factors for suicidal behaviours. Although the evidence to support school-based selective prevention is lacking, results from family-based selective prevention are promising.
The third preventative strategy is indicated prevention and crisis support, such as crisis hotlines that respond to the immediate distress calls from suicidal individuals. Formal evidence for their effect in the adolescent population is, however, lacking.
In summary, Cha et al highlight the notable advances made in understanding the epidemiology and (potential) etiology of suicidal behaviours. The researchers hope that future research will (i) improve the definitions of suicidal behaviours in the literature and be more representative of the most high-risk populations, (ii) clarify the etiology of suicide by integrating findings from various disciplines, and (iii) assess the developmental nature of suicide risk. They reinforce that future research must now focus on what, how and who is studied, to inform treatment and ultimately prevent suicide attempts in adolescents.
Referring to: Cha, C.B., Franz, P.J., Guzman, E.M., Glenn, C.R., Kleiman, E.M. & Nock, M.K. (2018), Annual Research Review: Suicide among youth – epidemiology, (potential) etiology, and treatment. J Child Psychol Psychiatr, 59: 460-482. doi:10.1111/jcpp.12831
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Sexual minority: a group of individuals whose sexual identity, orientation or characteristics differ from the majority (usually heterosexuals) in the surrounding society
Affective process: characteristic emotional reactions and temperaments to a situation
Interpersonal connectedness: the sense of belonging based on having sufficient quantity and quality of social contacts
Randomized controlled trials: an experimental setup whereby participants are randomly allocated to an intervention/treatment group or a control/placebo group; randomization of participants occurs after assessments for eligibility, and is used to minimize selection bias
Longitudinal study: study design where subjects are monitored over a period of time with continuous assessment of the study variables (i.e. risk factors or health outcomes)
Integrated Cognitive Behavioural Therapy (I-CBT): a combination of individual and family CBT techniques and parent training
Attachment-based Family Therapy: family therapy in which the parent and child work to repair problems in their relationship and to rebuild an emotionally secure relationship
Dialectical behaviour therapy (DBT): a modified form of cognitive behavioural therapy to help those who experience intense emotions. DBT focuses on changing unhelpful behaviours whilst accepting who you are
Interpersonal psychotherapy: brief, attachment-focused therapy for those with mood disorders that aims to resolve interpersonal problems and promote symptomatic recovery
Genome wide association study (GWAS): an observational analysis of a genome-wide set of genetic variables in a large cohort to see if any genetic variant is associated with a particular trait