Adolescent Victimization and Self-Injurious Thoughts and Behaviors: A Genetically Sensitive Cohort Study

Abstract

Objective: Victimized adolescents have an increased risk of self-injurious thoughts and behaviors. However, poor understanding of causal and non-causal mechanisms underlying this observed risk limits the development of interventions to prevent premature death in adolescents. This study tested whether pre-existing family-wide and individual vulnerabilities account for victimized adolescents' increased risk of self-injurious thoughts and behaviors.

Method: Participants were 2,232 British children followed from birth to 18 years of age as part of the Environmental Risk Longitudinal Twin Study. Adolescent victimization (maltreatment, neglect, sexual victimization, family violence, peer/sibling victimization, cyber victimization, and crime victimization) was assessed through interviews with participants and co-informant questionnaires at the 18-year assessment. Suicidal ideation, self-harm, and suicide attempt in adolescence were assessed through interviews with participants at 18 years.

Results: Victimized adolescents had an increased risk of suicidal ideation (odds ratio [OR] 2.40, 95% CI 2.11-2.74), self-harm (OR 2.38, 95% CI 2.10-2.69), and suicide attempt (OR 3.14, 95% CI 2.54-3.88). Co-twin control and propensity score matching analyses showed that these associations were largely accounted for by pre-existing familial and individual vulnerabilities, respectively. Over and above their prior vulnerabilities, victimized adolescents still showed a modest increase in risk for suicidal ideation (OR 1.45, 95%CI 1.10-1.91) and self-harm (OR 1.50, 95% CI 1.18-1.91) but not for suicide attempt (OR 1.28, 95% CI 0.83-1.98).

Conclusion: Risk for self-injurious thoughts and behaviors in victimized adolescents is explained only in part by the experience of victimization. Pre-existing vulnerabilities account for a large proportion of the risk. Therefore, effective interventions to prevent premature death in victimized adolescents should not only target the experience of victimization but also address pre-existing vulnerabilities.

Keywords: adolescence; self-harm; suicidal ideation; suicide attempt; victimization.

Figure 1

Distribution of Self-Injurious Thoughts and Behaviors in Adolescence Note:(A) Overlap between adolescent suicidal ideation, self-harm, and suicide attempt. The size of the circles and their overlap is proportional to the number of participants (N = 2,055). Suicidal ideation was correlated with self-harm (r = 0.80, p < .001) and suicide attempt (r = 0.89, p < .001). Self-harm was correlated with suicide attempt (r = 0.79, p < .001). (B) Prevalence of self-injurious behaviors endorsed by more than 1% of those who reported self-harm or suicide attempt. Girls and boys did not differ in types of self-injury reported, except for cutting/stabbing self (more prevalent in girls; odds ratio 1.94, p = .021) and hitting self/object (less prevalent in girls; odds ratio 0.24, p < .001). Please note color figures are available online.

Figure 2

Association Between Adolescent Victimization and Self-Injurious Thoughts and Behaviors Note:DZ = dizygotic; MZ = monozygotic. Please note color figures are available online.

Figure 3

Propensity Score for Adolescent Victimization in Non-Victimized and Victimized Adolescents Based on Child-Specific Characteristics Note: The propensity score was derived based on the following child-specific characteristics: childhood victimization, social isolation, IQ, internalizing problems, externalizing problems, self-harm, openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism. We used 1:1 nearest neighbor matching with replacement to match each study member to a study member with a similar propensity score in the opposite “treatment” group (eg, victimization [n = 671] or no victimization [n = 1,265]). Please note color figures are available online.