Introduction
School Bullying Victimization (SBV) is characterized by recurring aggressive actions—be they physical, verbal, or interpersonal—that take place within a power-differentiated relationship [
1]. SBV is particularly prevalent among adolescents with special educational needs [
2], especially those with Autism Spectrum Disorder (ASD) [
3]. The distinctive vulnerabilities of individuals with ASD—including communication deficits, atypical interests, stereotyped behaviors, and limited friendships—contribute to their increased susceptibility to SBV [
3,
4]. These vulnerabilities are exacerbated in mainstream educational settings, where students with ASD encounter SBV more frequently than in specialized environments [
5], with a noted peak during middle school years (roughly ages 12–15) [
6]. Such experiences are not only immediately distressing but can lead to a cascade of adverse long-term effects, including academic difficulties [
7], and mental health challenges such as anxiety, depression [
8], loneliness, and even suicidal ideation [
9]. Identifying and understanding the array of risk factors that contribute to SBV among adolescents with ASD placed in regular classes is thus a critical step toward developing effective interventions.
According to socio-ecological theory [
10], it is vital to identify risk factors associated with increased SBV among adolescents with ASD from different perspectives, covering individual characteristics, school and peers. First, from a developmental perspective, children's characteristics such as age, gender, and severity of ASD symptoms may shape SBV. Researchers have found that boys generally tend to be victimized more than girls [
11] and SBV peaks during the age of 12–15 [
6]. Others include social vulnerability [
12], living in a low-income household [
13], severity of Asperger syndrome symptomatology [
14] were identified as risk factors for SBV among children with ASD. Notably, high level of perceived stigma of adolescents show many victim characteristics, such as low self-esteem, low self-confidence, and high level of loneliness [
15], and do easily attract bullies [
25]. Schools, as an important places for students' daily lives, have a significant impact on being bullied [
16]. In light of this, research has begun to identify the risk factors at school associated with an increased likelihood of exposure to bullying. For example, Thornberg et al. [
17] found that as a negative interpersonal interaction phenomenon in youth, SBV can be predicted by adolescents' negative interpersonal relationships with teachers. Similarly, Goldweber et al. [
18] found school connection to be the strongest predictor of being bullied among young people. Because peers play a critical socialization role during childhood and adolescence [
19], peer relationships are likely implicated in the consideration of risks and protective processes related to victimization. Reciprocated peer relationships are negatively related to victimization [
20], while lack of peer support may prevent adolescents from developing social skills normally, making them more likely to be ostracized by peers and becoming targets of being bullied [
21]. As with typically developing children, having close friends protects against SBV [
22].
Although these studies largely help us understand SBV in youth from different levels of risks, prior studies have often failed to consider these factors' cumulative effect, potentially leading to an overemphasis on isolated risks [
23]. Moreover, risk factors in different fields are often synergistic, and individuals are often faced with risk factors in one filed as well as in another [
24]. Although single risks such as peer relationships, school belonging, and perceived stigma have been identified [
18,
20,
25], their synergistic effect remains under-examined. In the context of ASD, it is hypothesized that as the number of risk factors to which an individual with ASD is exposed increases, so will their vulnerability to becoming the victim of bullying. It is critical to consider multiple risks simultaneously and examine how they interact to influence their likelihood of experiencing SBV.
Existing literature has shown that the cumulative risk model is the most widely used method for modeling multiple risks [
24]. Prior research have found that cumulative risk models could show different functional forms: linear and nonlinear models [
26,
27]. A linear model shows that the steady increase in risk is proportional to the outcome [
28], suggesting that comprehensive prevention effort is essential. A nonlinear model can be further divided into ''positive acceleration'' and ''negative acceleration'' based on regression coefficients [
27]. The positive acceleration model describe a quadratic relationship where there is a disproportionate increase in the SBV mean score beyond a certain threshold as the cumulative risk score increases, making intervention challenging [
29]. The negative acceleration model assumes that the impact of new risk factors on individual decreases with the increase of cumulative risk, implying interventions for individuals with a medium number of risk factors is more effective [
29]. Therefore, exploring different functional forms between cumulative risk and SBV of adolescents with ASD were important because different functional forms can mean different intervention practices for SBV.
To our knowledge, existing literature has yet to explores vulnerability to bullying from a cumulative risk perspective among young people with ASD except Hebron's work [
14]. However, the findings of Hebron's work relied solely on parent or teacher reports of SBV, which may not fully align with the self-reported experiences of adolescents with ASD—a discrepancy that could overlook instances occurring beyond their direct observation [
30]. Additionally, cultural differences might also influence the SBV and maladjustment relationship [
31], suggesting that Hebron's findings from Western countries may not universally apply, particularly in lower SBV incidence regions like China [
32]. Thus, the first aim of this study is to elucidate the cumulative risk effect on SBV based on self-reports from adolescents with ASD in China and to map out the constellation of risks they face in mainstream educational settings.
The same level of cumulative risk does not necessarily result in identical adverse outcomes for everyone [
33]. It is thus crucial to identify potential factors that may indirectly link cumulative risk to SBV, such as internalizing problems. Internalizing problems often develop silently, manifesting as anxiety, depression, and loneliness, potentially disrupting typical developmental trajectories [
34]. They not only compromise adolescents' well-being but also heighten the risk for peer victimization [
35]. Children and adolescents who struggle internally may exhibit behaviors or emit signals that bullies perceive as vulnerabilities, thus becoming easier targets [
36]. The burgeoning body of research supports the notion that internalizing problems both contribute to and exacerbate the severity of SBV [
37‐
40].
Moreover, the functional form between cumulative risk and depression shows a positive acceleration model [
28,
41]. Such risks not only predict current problematic behavior but also increase future depression [
27,
42]. One study has confirmed the relationship between cumulative risks and internalizing problems [
43]. These dynamics underscore the importance of understanding the mechanisms through which cumulative risk translates into SBV, particularly in the context of ASD where internalizing problems may be more prevalent due to the inherent social communication challenges and environmental stressors faced by these individuals [
44]. There is a significant gap in research exploring how these risks, when aggregated, influence the trajectory and intensity of internalizing problems, and in turn, the occurrence of SBV in populations with ASD. Therefore, the second aim of the current study is to explore the relationship between cumulative risk and SBV by examining the potential mediation of Internalizing problem.
Based on the abovementioned review, we put forth two specific hypotheses as follows:
Hypothesis 1: There is a cumulative risk effect on SBV exposure among adolescent with ASD.
Hypothesis 2: Internalizing problem played a partial mediating role in the effect of cumulative risk on SBV.
Discussion
The current study underscores the role of cumulative risk as a significant predictor of heightened school bullying victimization (SBV) among adolescents with Autism Spectrum Disorder (ASD) in mainstream classes. Furthermore, it delineates the nonlinear pattern of the quadratic function (negative acceleration model) between cumulative risk and SBV, while also highlighting the direct and indirect influence of cumulative risk on SBV via the mediation of internalizing problems.
Mirroring earlier studies [
14], our results demonstrate that a higher cumulative risk correlates with increased SBV among adolescents with ASD. Moreover, we observed a nonlinear pattern (quadratic function) with a negative acceleration between cumulative risk and SBV. Specifically, the rate of SBV exposure escalates substantially with an increasing number of cumulative risks until it reaches a saturation point (four risks in this study), beyond which further increases in risk factors have a diminished ''plateau'' effect. This can be explained from two perspectives. First, when an individual faces risks from at least two domains concurrently, the risk of SBV exposure is severely augmented. Once the cumulative risk reaches a certain threshold, the impact of additional risk factors on bullying saturates. Second, following the study by Jones et al. [
43], the ''trigger point'' for substantial adjustment difficulties falls between three and four risks. Therefore, SBV increases linearly with the number of cumulative risks at lower risk levels (e.g., two or three risks). Upon reaching the trigger point (four in this study), the rate of SBV escalates sharply, plateaus, and maintains a relatively high level. These findings provide tentative support for the cumulative risk hypothesis regarding the SBV of adolescents with ASD [
41,
42] and offer evidence for intervention strategies targeting SBV.
With regard to the mediating effect of internalizing problems, we found that cumulative risk could lead to conditions such as depression, anxiety, and social phobia, which in turn could precede subsequent SBV. Consistent with prior research [
28], we determined that cumulative risk is positively associated with internalizing problems. Socio-ecological theory [
54] asserts that human development is influenced by multiple ecological subsystems, such as family, school, and peers. Long-term exposure to a poor school climate [
6], unhealthy family environment [
55], and weak interpersonal relationships [
11] can lead to various internalizing problems. These internalizing issues can negatively affect peer relationships, prompt stronger emotional reactions in ambiguous situations, and contribute to increases in SBV [
56]. By contrast, individuals exposed to fewer cumulative risks experience lower levels of internalizing problems, which can help in avoiding SBV. These findings underscore the pivotal role of internalizing problems in the pathway from cumulative risk to SBV.
The findings of this study have critical implications for intervention programs targeting adolescents with ASD experiencing SBV. Firstly, increased attention should be paid to external factors, as a growing body of research points to the importance of contextual risk factors [
4,
15]. Interventions need to extend beyond individual-level risk factors and address contextual influences that potentially heighten the risk of adolescents being bullied. For instance, recent studies have shown the effectiveness of parent-assisted learning in developing social skills among children with ASD [
57], and interventions with peer groups have been found to impact SBV [
15]. Secondly, it is essential to consider the number of identified risks to which adolescents with ASD are exposed, and interventions should aim at reducing the overall number of risks in their lives rather than focusing solely on the specific risks present. Finally, efforts should be made to mitigate internalizing problems in adolescents with ASD. Recommendations have been made for children with ASD who experience internalizing problems to seek help from mental health agencies [
58]. Psychotherapy approaches for children and their families have been shown to be beneficial in improving relationship skills [
57], which are often areas of difficulty for children with ASD.
Despite the significant contributions of this study, several limitations should be addressed in future research. Firstly, as our study relies on cross-sectional data, we were unable to obtain comprehensive longitudinal data, which is crucial for establishing causality. Secondly, our measure of multiple risk, the cumulative risk index, is additive and does not consider potential interactions between risk factors or the differential impact of individual risks on the outcome variable [
23]. More nuanced indices of multiple risk exposure could improve the validity of future studies. Furthermore, due to the limitations of secondary data analysis, certain potential confounding variables, such as ethnicity and IQ, were not included as they were not surveyed in SNELS. Despite controlling for students' adaptability and social-emotional skills, the omission of other confounders remains a limitation of this study. Thirdly, our focus on ASD restricts the generalizability of our findings. Subsequent studies should seek to replicate our findings with other populations. Lastly, although the variance explained by each model was statistically significant, it was relatively small. Future research should consider other risk factors that are not included in the current risk indexes for a more comprehensive understanding of adolescents with ASD of bullying victimization.
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