The concurrence of physical fight and sexual violence substantially increased the relative risks for attempted suicide and injurious suicide attempt among adolescent suicide ideators. The pattern of associations were different among two sexes: among female, the association between physical fight and/or sexual violence and suicide behaviors were more prevalent; in males, the concurrence of physical fight and sexual violence was associated with remarkably higher risk for injurious suicide attempt. High rates of suicide-attempt associated risk behaviors, as well as a high cumulative number of risk behaviors were observed among the population with concurrent physical fight and sexual violence, especially among males.
Both physical fight and sexual violence had been known as risk factors/predictors for suicidal behaviors among adolescents and adults 12–15. For example, the YRBS data showed that high school students who reported attempting suicide during the preceding 12 months were more likely also to have reported fighting than those who reported not attempting suicide (61.5% vs 30.3%)15. Stack et al. reported that involvement in physical fighting raised the odds of a suicide attempt by 2.18 times 13. A experience of sexual violence was found to be associated with increased risk of suicide attempt among both high school male and female students (OR = 11.3 and 4.54, respectively; P < 0.05)14. Consistent with previous findings, our analyses showed both factors were associated with increased risk of suicide attempt. The potential role of physical fight and sexual violence in the suicidal behavior trajectory may be understood within the context of the interpersonal theory of suicide 2. According to the interpersonal theory, three constructs, namely thwarted belongingness, perceived burdensomeness, and the acquired capability for suicide, are needed for an individual to attempt suicide. The capability for suicide could be acquired by both increased physical pain tolerance and reduced fear of death through habituation to the physically painful and fearful aspects of self-harm 2. Drawing on the interpersonal theory of suicide, physical fights may serve as a risk factor for suicidal behaviors by increasing the individual’s acquired capability for suicide. In support of this explanation, one study had reported that individuals who reported engaging in physical fights had higher acquired capability scores 21. The experience of sexual violence might lead to suicidal desires by increasing the victim’s sense of perceived burdensomeness and thwarted belongingness; moreover, it may increase the victim’s capability for suicide by increasing the habituation to the pain and fear in suicide 14.
Our analyses showed that among the four study groups (physical fight –/ sexual violence –, physical fight –/ sexual violence +, physical fight +/ sexual violence –, and physical fight +/ sexual violence +), the group with concurrent physical fight and sexual violence had the highest risks of suicide attempt (RR = 2.01, 95%CI: 1.74, 2.31), suicide plan (RR = 1.22, 95%CI: 1.11, 1.33), and injurious suicide attempt (RR = 4.03, 95%CI: 2.81, 5.78). Since physical fight and sexual violence along could increase the individual’s capability for suicide, it is possible that the concurrence of two exposures could further increased the individual’s capability for suicide, resulting in higher rates of suicide attempt and suicide plan. More importantly, the concurrence of physical fight and sexual violence raised the risk of injurious suicide attempt by 4 times, suggesting that the combination of physical fight and sexual violence is associated with more severe forms of suicide attempt. This finding has both theoretical and practical implications. First, it suggests that when conceptualize theory of suicide, it is necessary to consider how multiple risk factors could influence the suicide behavior. The acquired capability for suicide might accumulated through multiple risk factors, and the amplified capability could result in more lethal suicide behaviors. For practical uses, our findings demonstrated that in searing for predicting factors for suicide attempt among ideators, it is imperative to examine the effects of different combinations of risk factors. And our results emphasis the need for targeted prevention and intervention efforts in youth with concurrent experience of physical fight and sexual violence.
Our study observed associations between physical fight/sexual violence and a wide variety of health-risk behaviors, many of which had been reported in previous studies 17,19,22,23. For example, weapon-carrying was found to be associated with increased involvement in physical fighting 19, and early alcohol use initiation and heavy drinking was associated with comorbid fight and suicide attempts among adolescent 23; a history of adolescent sexual victimization was found to be associated with increased likelihood of cigarette smoking, marijuana use, multiple sexual partners, and early sexual intercourse among college women 17. Considering that the risk behavior we investigated were selected from factors that associated with the risk of suicide attempt, the observed association between physical fight and/or sexual violence and the risk of suicide attempt could be a result of combined effects of the clustered risk factors. The clustered factors could interact as both cause and effect, and influenced the suicidal behavior through complex pathways, therefore isolating the effects of single factors might not practical. Also, interventions targeting single factors might not powerful enough for the prevention of suicidal attempts. The problem behavior theory suggested that the risk-health behaviors might cluster together because they serve similar psychological and social developmental functions 20. Therefore, for the purpose of developing intervention plans, it is important to identify the key factors that leads to subsequent risk behaviors and to identify reversible factors that could serve as intervention targets.
Among both sexes, the concurrency of physical fight and sexual violence was associated with a high risk for injurious suicide attempt. 26.5% of female students with concurrent physical fight and sexual violence reported injurious suicide attempt; among male students, the rate was 32.8%. The RR for injurious suicide attempt was remarkably higher among male (RR = 6.19, 95%CI: 3.3, 12.14) than female (RR = 3.25, 95%CI: 2.09, 5.04), using the risk in the (physical fight –/ sexual violence –) group in the same sex as the reference. Sex difference in the suicidal behavior has consistently been observed. In most part of the world, females are more likely than men to attempt suicide, and they are less likely to die by suicide 16. One explanation from the interpersonal theory of suicide is that females are less likely to develop the acquired capability for suicidal behavior that are men, because females generally experiences fewer events that could reduce their fear of self-injury through habituation (e.g., exposure to guns, physical fights, violent sports, etc.), and females have lower pain and fear tolerance than men 2. Our finding supported this explanation in that among the youth with concurrent physical fight and sexual violence, males reported more health-risk behaviors than females (male: median = 14, range: 2–40; female: median = 12, range: 0–33; P = 0.0023). This finding adds empirical evidence for the understanding of sex difference in suicidal behaviors, and again strengths the importance of examining an individual’s risk factor profile when evaluating the suicide risk.
Strengths of this study include the novel investigation of the association between concurrent physical fight and sexual violence and the risk of suicide attempt among adolescent suicide ideators, and the cumulative number of suicide risk factors among several sub-populations. In searching for risk factors that could differentiate attempters from ideators, most of previous studies examined the effects of single factors. The findings of our study emphases that in both researches and intervention practices, the individual’s risk of suicide behaviors should be conceptualized as a combined effects of multiple factors. The cumulative number of suicide risk factors also helps understand the remarkable higher rates of injurious suicide attempt among adolescent males with concurrent physical fight and sexual violence. Besides, when estimating the strength of association between risk factors and suicide behaviors, unlike studies that used logistic regression to estimate the OR, we used log binomial regression to estimate the RR and AR which are more intuitive and can be better interpreted 24.
This study has several limitations. First, the cross-sectional design of the study limits our ability to make causal inferences. It is possible that some of the reported experiences of physical fight and sexual violence were occurred after the suicide attempt. Nevertheless, the identified patterns could still be informative for the understanding of how the suicide-related risk behaviors clustered and for the identification of high risk populations that need multiple behavior interventions. Longitudinal studies are needed to test the causality relationship between sexual violence, physical fight, and suicide behaviors. Second, the YRBS data are collected from self-reported questionnaires, the answers would subject to recall bias and classification error which was caused by individual’s different understanding of the queries. Third, the YRBS is a school based survey, therefore may not representative for adolescents who did not attend school. Lastly, findings of this study are draw from the adolescents from the United States, the combined effects of could be different under different culture and social-development conditions 25. To improve the understanding of the suicide behaviors and promote effective interventions, future research is needed to validate these findings in different counties and populations.
To conclude, the concurrence of physical fight and sexual violence substantially increased the risks for attempted suicide and injurious suicide attempt among adolescent suicide ideators. A wide variety of risk behaviors clustered with the concurrence of physical fight and sexual violence, especially among males, which possibly lead to the higher rate of injurious suicide attempt among male students. Further study is needed to explore the mechanism of how combined risk factors works in the suicide pathways. And to guide the development of suicide intervention strategies, it is important to identify the key factors that leads to subsequent risk behaviors and to identify reversible factors that could serve as intervention targets.