Bidirectional association between bullying perpetration and internalizing problems among youth

Abstract

Purpose

Identification of the temporal pattern of associations between bullying perpetration and mental health problems among youth is needed for the optimal targeting of intervention and prevention. We examined the bidirectional association between bullying perpetration and internalizing problems among youth in the United States.

Methods

We used data from the prospective cohort study of the Population Assessment of Tobacco and Health waves 1 (September 12th 2013 to December 14th 2014) and 2 (October 23rd 2014, to October 30th 2015), a nationally representative sample of youth. We analyzed the associations of bullying perpetration with internalizing problems using binary and multinomial logistic regressions. The 13,200 youths aged 12–17 years were included in the analytic sample.

Results

There was a cross-sectional association between bullying perpetration and moderate/high lifetime internalizing problems (OR_{moderate vs no/low}=3.13, 95% CI 2.67–3.65; OR_{high vs no/low}=8.77, 95 % CI 7.53–10.20). In the prospective analyses, bullying perpetration was associated with increased likelihood of moderate/high internalizing problems at follow-up (OR_{moderate vs no/low}=1.49, 95% CI 1.15–1.94; OR_{high vs} no/low=1.71, 95 % CI 1.23–2.38) and youth with moderate/high internalizing problems had higher odds of bullying perpetration at follow-up (OR_moderate=1.95, 95% CI 1.65–2.31; OR_high=3.21, 95 % CI 2.74–3.76).

Conclusions

The association between bullying perpetration and internalizing problems appears to be bidirectional. Bullying behaviors prevention and intervention strategies among youth should consider how to take into account and handle negative feelings and mental health problems.

INTRODUCTION

Bullying is defined as “any unwanted aggressive behavior(s) by another youth or group of youths, who are not siblings or current dating partners, involving an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated” [1]. A meta-analysis of 80 studies estimated that 36.0% (95 % CI 35.8–36.2) and 34.5% (95 % CI 34.3–34.8) of adolescent experienced bullying victimization and perpetration respectively [2]. In the United States, recent national surveys provide prevalence of bullying. The 2017 School Crime Supplement of the National Crime Victimization Survey, a survey of students aged 12–18 in public and private elementary, middle and high schools as well as home-schooled youth, found that 20.2% (standard error of 0.71) of students reported being bullied during the school year [3]. The 2017 Youth Risk Behavior Surveillance, an epidemiological surveillance system developed by the Centers for disease Control and Prevention, showed that 19.0% (95 % CI 17.6–20.5) of high school students in grades 9^th–12^th were bullied during the 12 months before the survey [4]. The most recent 2013–2014 Health Behaviour in School-Aged Children Survey, an international study conducted in collaboration with the World Health Organization Regional Office in Europe, found that 27.6% of children aged 11–15 were bullied and that 25.3% bullied others during the past couple of months [5].

An extensive number of studies have focused on the causes and consequences of bullying victimization, a well-recognized global public health issue [1,6]. In particular, it is well documented that bullying victimization is associated with immediate and life-long mental health problems [6]. In contrast, prior research on the causes and consequences of bullying perpetration is more scattered. Previous studies have linked bullying perpetration to high risk for mental health problems such as depression [7–10], anxiety [9–11], psychological distress [12], psychosomatic symptoms [9], and suicidal behaviors [7,12,13]. However, other studies find no support for adverse outcomes [14–16]. Most of these studies were cross-sectional [7–10,12], making it difficult to determine the temporal sequence between bullying perpetration and mental health problems. Moreover, no studies have examined the hypothesis that the relationship between bullying perpetration and mental health problems may be bidirectional. Longitudinal studies with repeated measures on bullying perpetration and mental health problems are required to address these two causal directions.

Therefore, in this study, we examined the bidirectional association between bullying perpetration and internalizing problems, among youth in the United States using data from a nationally representative longitudinal study.

METHODS

Study design and participants

The Population Assessment of Tobacco And Health (PATH) Study [17], conducted from September 12^th 2013 to December 14^th 2014 (wave 1), is a nationally representative longitudinal study on tobacco use behavior, attitudes and beliefs, and tobacco-related health outcomes, supported by the US National Institutes of Health and Food and Drug Administration. The PATH Study recruited 32,320 adults (18 years and older) and 13,651 youth (12–17 years) via an address-based, area-probability sampling approach, using an in-person household screener. The study oversampled adult tobacco users, young adults (aged 18–24 years), and African-American adults. Generally, up to two youth were sampled per household. After obtaining consents from adults, parents, emancipated youth and assent from youth, data were collected via Audio Computer-Assisted Self-Interviews in English or Spanish. The weighting procedures adjusted for oversampling and nonresponse, allowing estimates to be representative of the non-institutionalized, civilian U.S. population aged 12 years and older. At wave 1, the weighted response rate for the household screener was 54.0%. Among screened households, the overall weighted response rate at wave 1 was 74.0% for the adult interview and 78.4% for the youth interview. Wave 2 interview was conducted as close as possible to the 1-year anniversary of each respondent’s wave 1 interview (weighted response rate: adult interview, 83.2%; youth interview, 87.3%). More details about the study design and methods are presented elsewhere [17]. The Westat Institutional Review Board approved the study design and protocol to safeguard the rights, welfare and well-being of all humans involved in this study; the Office of Management and Budget approved the data collection.

For the purpose of this study, we used the PATH Study Public-Use Files from waves 1 (2013–2014) and 2 (2014–2015). Only youth participants with complete data at wave 1 on variables used for the associations examined were included (N=13,200, Figure 1). Compared with youth participants included in the analysis, those excluded (N=451) were younger and more likely to be in middle school; no major differences existed in sex and race/ethnicity. Of the 13,200 youths included, 11,615 were successfully screened at wave 2 (Figure 1). Compared to them, youth participants lost to follow-up (N=1,585) were older and more likely to be in other grade level; no major differences existed in sex and race/ethnicity.

Figure 1.

Flow diagram

Measures

Lifetime bullying perpetration

Bullying perpetration was assessed at wave 1 (2013–2014) and 2 (2014–2015) by asking youth participants “when was the last time that you were a bully or threatened other people two or more times?” and response choices were: never, over a year ago, 2 to 12 months ago, and past month. Bullying perpetration was dichotomized and defined as lifetime bullying perpetration (no vs yes).

Lifetime internalizing problems

Internalizing problems were assessed at wave 1 (2013–2014) and 2 (2014–2015) via the internalizing problems subscale of the Global Appraisal of Individual Needs – Short Screener (GAIN-SS), modified for the PATH Study [18]. Items for the GAIN-SS were derived from the GAIN-Initial instrument that is a standardized biopsychosocial that integrates clinical and research assessment for people presenting to substance abuse or other behavioral health treatment [19]. The subscale included four items: (1) feeling very trapped/sad/depressed, (2) trouble sleeping, (3) feeling nervous/anxious/tense/scared, (4) being distressed/upset about the past; across four time periods: never, over a year ago, 2 to 12 months ago, and past month. The number of responses endorsed in the lifetime were summed for the internalizing problems subscale (complete data for the four components were required). Summary score ranged from 0 to 4. Based on the number of items endorsed, youth participants were categorized into three levels of severity: no/low (0 or 1 items), moderate (2 or 3 items), high (4 items). These cut-points were informed by previous study showing concurrent and predictive validity in other samples [18,20]. Individuals categorized as no/low severity are unlikely to have a diagnosis or need services, moderate severity identifies individuals who have a possible diagnosis and are likely to benefit from a brief interventions, and high severity identifies individuals who have a high probability of a diagnosis and need more formal assessment and intervention [19]. These cut-points were also used by a previous study on the same sample [21] and, based on Cronbach’s alpha calculated for the current PATH Study sub-sample cut-point, the reliability of the lifetime internalizing problems subscale was 0.81 at wave 1 and 0.82 at wave 2, suggesting that the items had relatively high internal consistency.

Covariates

Baseline covariates (wave 1) were used as potential confounding variables. Sociodemographic characteristics included sex (male, female), age (12–14, 15–17 years old), race/ethnicity (white non-Hispanic, black non-Hispanic, other non-Hispanic, Hispanic) and education (middle school, high school, and other including not enrolled, home-schooled, school where students are not assigned to a particular grade, college or vocational school).

Statistical analysis

Differences in baseline characteristics of youth participants as a function of lifetime bullying perpetration were assessed using Chi-squared test. To study the relationship between bullying perpetration and internalizing problems, we undertook different analyses. First, cross-sectional analysis aimed to assess the associations between lifetime bullying perpetration and lifetime internalizing problems at baseline (wave 1). Second, the prospective analysis, undertaken among participants with no/low internalizing problems at wave 1, examined the association between lifetime bullying perpetration at wave 1 and incidence of internalizing problems at wave 2. Third, the prospective analysis examined the association between lifetime internalizing problems at wave 1 and subsequent bullying perpetration at wave 2 among participants who never declare bullying perpetration at wave 1.

To explore these associations, we ran two type of logistic regressions, one multinomial (with internalizing problems as dependent variable) and one binary (with bullying perpetration as dependent variable). ORs were adjusted for sociodemographic characteristics: sex, age, race/ethnicity, and education. All estimates were weighted to represent the U.S. youth population; percentages (%), standard errors (se), ORs and confidence intervals (CIs) were estimated using the balanced repeated replication (BRR) method [22] with Fay’s adjustment set to 0.3 to increase estimate stability [23]. All analyses were conducted using Stata software, version 15 (StataCorp, 2017).

Sensitivity analyses

To test the robustness of our findings, we undertook several sensitivity analyses. We first conducted the same cross-sectional and longitudinal analyses to examine the associations between past year bullying perpetration and lifetime internalizing problems. In order to do this, we created a three-category variable for ‘bullying perpetration’ at baseline (wave 1) as: (1) never; (2) over a year ago; and (3) past year. Second, we examined the association between past month bullying perpetration and lifetime internalizing problems. For this step, we created a three-category variable for ‘bullying perpetration’ at baseline defined as: (1) never; (2) over a month ago; and (3) past month.

RESULTS

Study population

Among 13,651 youth (12–17 years) of the PATH study, 13,200 had complete data on all variables at baseline and were included in the cross-sectional analysis (Figure 1). Table 1 shows the baseline characteristics of the participants overall and according to lifetime bullying perpetration at wave 1. In brief, 21.0% reported lifetime bullying perpetration, 29.7% and 33.8% experienced moderate and high lifetime internalizing problems respectively.

Table 1.

Baseline participant’s characteristics of the PATH study by lifetime bullying perpetration (wave 1, 2013–2014).

Characteristics	Overall N=13,200 (Population size 24,050,521)			Lifetime bullying perpetration
				No N=10,421 (79.0%)			Yes N=2,779 (21.0%)			P
	n	%	SE	n	%	SE	n	%	SE
Sex										0.556
Male	6761	51.3	0.08	5341	78.8	0.49	1420	21.2	0.49
Female	6439	48.7	0.08	5080	79.2	0.58	1359	20.8	0.58
Age										0.674
12–14 years old	6692	49.9	0.09	5296	79.2	0.52	1396	20.8	0.52
15–17 years old	6508	50.1	0.09	5125	78.8	0.57	1383	21.2	0.57
Race/Ethnicity										<0.001
White, non-Hispanic	6399	54.6	0.09	4959	77.6	0.51	1440	22.4	0.51
Black, non-Hispanic	1793	13.8	0.06	1428	79.1	1.00	365	20.9	1.00
Other, non-Hispanic	1223	9.3	0.06	940	80.3	1.27	283	19.7	1.27
Hispanic	3785	22.3	0.06	3094	81.9	0.82	691	18.1	0.82
Education (grade in school)										0.391
Middle school	4993	37.3	0.24	3976	79.7	0.63	1017	20.3	0.63
High school	6461	48.8	0.26	5066	78.5	0.57	1395	21.5	0.57
Other	1746	13.9	0.23	1379	79.0	0.98	367	21.0	0.98
Lifetime internalizing problems severity										<0.001
No/Low	4813	36.5	0.53	4472	92.8	0.45	341	7.2	0.45
Moderate	3931	29.7	0.46	3195	81.2	0.63	736	18.8	0.63
High	4456	33.8	0.57	2754	62.1	0.80	1702	37.9	0.80

Represents unweighted sample size (n).

Percentages (%) and standard errors (SE) are weighted to be representative of the US youth population (N= 24,050,521).

Lifetime internalizing problems were assessed using the Global Appraisal of Individual Needs - Short Screener (GAIN-SS) and categorized as no/low (0–1 symptoms), moderate (2–3 symptoms), and high (4 symptoms) severity levels.

P values are 2 sided (P).

Cross-sectional associations between lifetime bullying perpetration and lifetime internalizing problems

Table 2–A shows the adjusted ORs estimating the association of lifetime bullying perpetration and lifetime internalizing problems at baseline. Participants who reported perpetrating bullying were more likely to experience more severe lifetime internalizing problems (OR_{moderate vs no/low}=3.13, 95% CI 2.67–3.65; OR_{high vs no/low}=8.77, 95 % CI 7.53–10.20) compared to participants who reported not perpetrating bullying.

Table 2.

Cross-sectional and prospective associations between bullying perpetration and internalizing problems.

	OR	CI 95%	P
A- Cross-sectional association between lifetime bullying perpetration at wave 1 and lifetime internalizing problems at wave 1a
	Lifetime internalizing problems severity (wave 1), moderate vs no/low
Lifetime bullying perpetration (wave 1)			<0.001
No	reference
Yes	3.13	[2.67–3.65]
	Lifetime internalizing problems severity (wave 1), high vs no/low
Lifetime bullying perpetration (wave 1)			<0.001
No	reference
Yes	8.77	[7.53–10.20]
B- Prospective association between lifetime bullying perpetration at wave 1 and incident internalizing problems at wave 2b
	Internalizing problems severity, moderate vs no/low
Lifetime bullying perpetration (wave 1)			0.003
No	reference
Yes	1.49	[1.15–1.94]
	Internalizing problems severity, high vs no/low
Lifetime bullying perpetration (wave 1)			0.002
No	reference
Yes	1.71	[1.23–2.38]
C- Prospective association between lifetime internalizing problems at wave 1 and incident bullying perpetration at wave 2c
	Bullying perpetration
Lifetime internalizing problems severity (wave 1)			<0.001d
No/Low	reference
Moderate	1.95	[1.65–2.31]	<0.001
High	3.21	[2.74–3.76]	<0.001

Odds ratio adjusted for socio-demographic characteristics (sex, age, race/ethnicity, education).

OR, odds ratio; CI, confidence interval; P, p-values are 2 sided

^aResults are of participants with complete data at baseline, N=13,200 (Population size 24,050,521).

^bResults are of participants with no/low internalizing problems at wave 1 and participated at wave 1 and 2, N=4,104 (Population size 8,474,953).

^cResults are of participants who never declare bullying perpetration at wave 1 and participated at wave 1 and 2, N=9,107 (Population size 18,827,948).

^dtest for homogeneity among different lifetime internalizing problems severity classes.

Lifetime bullying perpetration as a predictor of internalizing problems

Table 2–B shows adjusted ORs for the association between lifetime bullying perpetration and incident internalizing problems at wave 2 among participants with no/low internalizing problems at wave 1 and who participated in wave 2.

Lifetime bullying perpetration at wave 1 was associated with incident moderate (OR_{moderate vs no/low}=1.49, 95% CI 1.15–1.94) and high (OR_{high vs no/low}=1.71, 95 % CI 1.23–2.38) internalizing problems, over the 1-year follow-up, in comparison to no/low internalizing problems.

Lifetime internalizing problems as a predictor of bullying perpetration

Table 2–C shows adjusted ORs for the association between lifetime internalizing problems and incident bullying perpetration at wave 2 among participants who never declare bullying perpetration at wave 1 and participated in wave 2.

Reporting moderate or high lifetime internalizing problems at wave 1 was associated with incident bullying perpetration (OR_moderate=1.95, 95% CI 1.65–2.31; OR_high=3.21, 95% CI 2.74–3.76), over the 1-year follow-up, compared to reporting no/low lifetime internalizing problems.

Sensitivity analysis

Among 13,200 participants, 79.0% reported they never bullied others, 10.9% reported having bullied others over a year ago, and 10.1% reported having bullied others in the past year (TableA1). When bullying perpetration was considered as a past month measure, 16.3% reported having bullied others over a month ago, and 4.7% reported having bullied others in the past month (TableA2).

Cross-sectional associations between bullying perpetration and lifetime internalizing problems

The results with bullying perpetration considered as a past year measure (TableA3–A) show that participants who reported perpetrating bullying over a year ago (OR_{moderate vs no/low}=3.15, 95% CI 2.53–3.91; OR_{high vs} no/low=7.50, 95 % CI 6.06–9.27) and in the past year (OR_{moderate vs no/low}=3.09, 95% CI 2.50–3.84; OR_{high vs} no/low=10.42, 95 % CI 8.57–12.66) were more likely to experience more severe lifetime internalizing problems compared to participants who reported not perpetrating bullying. When bullying perpetration was considered as a past month measure (TableA4–A), participants who reported perpetrating bullying over a month ago (OR_{moderate vs no/low}=3.28, 95% CI 2.72–3.96; OR_{high vs no/low}=8.69, 95 % CI 7.32–10.33) and in the past month (OR_{moderate vs no/low}=2.62, 95% CI 1.98–3.46; OR_{high vs no/low}=9.07, 95 % CI 7.07–11.64) were more likely to experience more severe lifetime internalizing problems compared to participants who reported not perpetrating bullying.

Bullying perpetration as a predictor of internalizing problems

TableA3–B, where bullying perpetration was considered as a past year measure, shows that bullying others in the past year was associated with new onset of moderate internalizing problems (OR_{moderate vs no/low}=1.62, 95% CI 1.12–2.35). Bullying others over year ago was associated with new onset of high internalizing problems (OR_{high vs no/low}=1.80, 95% CI 1.11–2.91). TableA4–B, where bullying perpetration was considered as a past month measure, shows that bullying others over a month ago was associated with new onset of moderate (OR_{moderate vs no/low}=1.48, 95% CI 1.08–2.04) and high (OR_{high vs no/low}=1.72, 95% CI 1.15–2.58) internalizing problems.

DISCUSSION

Key findings

We examined the bidirectional association of bullying perpetration with internalizing problems in a large cohort of youth. Cross-sectional analyses showed that bullying perpetration was associated with an increased probability of moderate/high lifetime internalizing problems. In prospective analyses, we found that bullying perpetration was associated with incident moderate/high internalizing problems at wave 2. On the other hand, exposure to lifetime moderate/high internalizing problems was associated with incident bullying perpetration at wave 2. Sensitivity analysis found similar patterns of association as those reported in the main analyses for both cross-sectional and longitudinal analyses.

Results in the context of previous studies

Among U.S. youth aged 12–17 years, we found that 21.0% reported bullying perpetration in the lifetime, 10.1% in the past year, and 4.7% in the past month. Several other national surveys provided prevalence of bullying behaviors among youth in the U.S. These include: the School Crime Supplement (SCS) to the National Crime Victimization Survey [3], the Youth Risk Behavior Survey (YRBS) [4], the National Survey of Children’s Exposure to Violence (NatSCEV) [24], the Health Behaviour in School-Aged Children survey (HBSC) [5,25], and the National Survey of Children’s Health (NSCH) [26]. Neither the SCS, the YRBS, nor the NatSCEV provide estimates of bullying perpetration. The most recent HBSC survey, in which the United States participated, is the 2009–2010. Students were asked “how often have you taken part in bullying another student(s) at school in the past couple of months?” and findings showed that 28.4% of U.S. students (aged 11, 13, and 15 years) bullied others at school in the past couple of months [25]. Results from the 2016 NSCH showed that 6.4% of children and adolescents (aged 6–17 years) were reported by their parents to bully others (bullying perpetration was assessed using the question “How well does the following phrase describe this child? This child bullies others, picks on them, or excludes them.”) [26]. The methods of assessment (e.g. definitions, question wording with vs. without context of time, self-reported vs. parent-reported), survey periods, and age range, could explain the difference of bullying perpetration prevalence between these studies and our study. However, we believe that our findings provides an important extension to previous literature.

Our cross-sectional results are consistent with previous studies showing similar associations of bullying perpetration with some components of internalizing problems (mainly depression and anxiety symptoms) [7–10].

The prospective finding of our study highlight a bidirectional association between bullying perpetration and internalizing problems. Bullying perpetration increases the risk of moderate/high internalizing problems, and these problems are also likely to be associated with bullying perpetration. Previous longitudinal research was mainly focused on the association between bullying perpetration and the incidence of internalizing problems [11,14,15]. Our results are consistent with findings from Kretschmer et al. [11] showing that bullying perpetration was linked to later anxiety in a cohort study conducted among Dutch adolescents over 10 years of follow-up. In contrast, Hemphill et al. [14] conducted a study among Australian students aged 12–14 years at baseline and found no association between bullying perpetration and later depressive symptoms. In the same vein, Copeland et al. [15] identified no association between bullying perpetration only and young adult psychiatric outcomes (depressive and anxiety disorders) in a community sample of children aged 9, 11 and 13 from 11 counties in Western North Carolina. Discrepancies with these findings could result from the limited sample size leading to insufficient power to detect a significant association or from the ability to take into account other bullying behavior, i.e. bullying victimization or from the consideration of disorders rather than symptoms as outcomes.

Possible explanations

Several hypotheses have been posited to explain the prospective association of bullying perpetration on mental health outcomes. Classmates tend to dislike youth who bully [27]. Youth who bully may become aware of their peer’s dislike and rejection, and might gradually feel negatively about the future and developed symptoms of anxiety and depression. Moreover, bullying perpetration could result in a worldview that is perpetually competitive and threatened by rivals [28]. Youth who engage in bullying might begin to view the world as aggressive and hostile, and as a coercive space filled with conflict where one’s status is mainly determined by power and control of others [29]. These might connect to a negative psychological cost as an ongoing struggle for dominance within a system where others dislike them.

Other mechanisms have also been proposed to explain the prospective association of mental health problems on bullying perpetration. First, the association between internalizing problems and incident bullying perpetration seems to be in line with the acting-out hypothesis that negative emotional states are acted out in externalizing behavior [30]. Second, youth with internalizing problems could be often “marginalized”, have low self-esteem, feel insecure and use bullying to fight a system that leave them out. The social capital theory [31], which refers to the benefits gained from social relationship, suggests that using bullying tactics could be a means of acquiring social capital, improving youth’s social status in the classroom or school in order to offset their marginalization. Third, similar to the idea of counterbalancing their “marginalization”, the dominance theory [32] suggests that bullying perpetration could be a means of obtaining and maintaining power and dominance to form an individual-based social hierarchy with one or a few dominant individuals at the top while subordinate individuals are forced to the bottom. Finally, youth who present internalizing problems are more likely to have family hardships such as low socioeconomic status, family instability, conflictual family dynamics and child maltreatment. Coercive cycles of family member-child interaction could lead youth to expect that coercion is fundamental to interpersonal relationships [33], which lead them to bully peers [34].

However, we were not able to test these mechanistic hypotheses and the precise mechanisms underlying the current observations remain to be further examined.

Strengths and limitations

To our knowledge, this is the first study to comprehensively examine bidirectional association between bullying perpetration and internalizing problems in a nationally representative sample of U.S. youth. Our study design allowed us to show that the association is likely to be bidirectional between bullying perpetration and internalizing problem. However, these findings should be interpreted with some limitations. First, bullying is traditionally defined in the literature using three typical features: intentional harm, repetition over time, and real or perceived imbalance of power [1]. Although perpetration measure in this study addressed repeated behavior, the measure did not address the imbalance of power or the intentionality dimensions. It is difficult to define clearly, to young children, the notion of power imbalance. Moreover, it is challenging to make it understandable to them. When asked about bullying, most students tended to focus primarily on negative actions such as being mean to or teased or threatened someone, regardless of whether or not it was repeated and whether or not it was in an unequal relationship [35]. Studies have found that students fail to recognize the power imbalance as a requirement for bullying and include other forms of peer aggression in their reports of bullying [36,37]. Moreover, in our study, bullying perpetration was measured based on a single-item question and did not define what bullying precisely entails or give examples thereof. Recent findings in the literature indicated that the use of a definition has no impact on prevalence rates [38]. However, bullying rates seems to be highly sensitive to the structure of the survey questions: using a single-item measure seems to yield lower prevalence rates of bullying than determining bullying based on a multiple-item approach [38,39]. Therefore, taking into account these issue related to the bullying measure, the prevalence estimates as reported in this study may overestimate or underestimate the true prevalence of bullying and in return, influence the strength of association between bullying perpetration and internalizing problems. However, the importance of looking more broadly at peer difficulties has been emphasized previously in the literature [40]. Assessing the impact of bullying, characteristics of individuals involved, and the broader landscape of those individuals’ strengths and well-being is important for intervention purposes. Second, data on bullying perpetration was based on self-reports and, due to the fact that bullying victimization was not assessed in the PATH study, we were neither able to study bullying victimization nor to disentangle those who were bullies-only from those who were bullies-victims (both being bullied and bullying others) among the perpetrator category. Cross-sectional studies show that these two groups have similar risk factors and outcomes, although bullies-victims tend to be exposed to more risk factors than bullies-only and to show worst mental health outcomes. Future research, with available data on bullying victims and perpetrators, should examine combinations of victimizations and perpetration. Third, internalizing problems were assessed via the GAIN-SS that measures severity of mental health symptomology rather than diagnosis. However, the high sensitivity and specificity between GAIN-SS items and diagnoses supports the use of symptoms as good indicators of clinically significant mental health problems [19]. Fourth, although we were able to control for a large range of potential confounding variables, the possibility of residual confounding from unmeasured variables cannot be ruled out. Finally, studies with longer follow-up would be needed to assess the long-term bidirectional association of bullying perpetration and internalizing problems.

Conclusion

Despite these potential limitations, the results of this study suggest that the association between bullying perpetration and internalizing problems is likely to be bidirectional. Bullying perpetration increases the risk of developing internalizing problems, and having internalizing problems increases the probability of bullying others. These findings suggest that intervention and prevention strategies warrant increased focus for reducing bullying behaviors should consider including strategies of addressing how to handle/providing support for negative feelings and mental health problems.

IMPLICATIONS AND CONTRIBUTION.

This study aims to understand the temporal pattern of association between bullying perpetration and internalizing problems in youth. Findings identify a bidirectional prospective association between bullying perpetration and internalizing problems suggesting that negative feelings and mental health problems are important targets in the bullying behaviors prevention/intervention strategies among youth.