Involvement in bullying behavior (as either a bully, a victim or both) in the absence of other risks in high school did not predict later depression, suicidal ideation or suicide attempts; however, it did portend an increased use of substances. Four years after the initial assessment, when all the students were no longer in high school, internalizing problems were still significantly less frequent among those who had only reported frequent bullying behaviors in high school compared to students identified as at-risk for suicidal behavior (based on suicidal ideation, suicidal behavior, depression or substance abuse); yet, levels of substance problems were comparable to those for youths identified as “at-risk” in high school. This appeared to be so regardless of whether the high school student had been the victim of bullying, the bully or both, and whether male or female. Overall, victims of bullying behavior were more depressed and suicidal than bullies, and those who were both victims and bullies continued to exhibit the most problems at follow-up.
Our findings are consistent with the only other follow-up study of high school students - a 2-year follow up of peer victimization among Australian youth - which found that victimization at baseline was not predictive of later “psychiatric health” after baseline health status was taken into account (Rigby, 1999
). Moreover, bullying behaviors among younger children have been reported to predict depression, but not necessarily suicidal ideation and behavior. Among a large birth cohort of Finnish boys, bullying behavior at age 8 was associated with severe depression, but not with suicidal ideation, 10 years later, when controlling for childhood depression (Klomek et al., 2008
). Additionally, it was bullies and victims with psychiatric symptoms at age 8 rather than all bullies or victims per se that were at elevated risk of later psychiatric disorders (Sourander et al., 2007
). In another study from the same birth cohort Sourander et al. (2009)
have reported that frequent victimization among girls but not among boys predicted psychiatric hospital treatment and use of psychopharmacologic medication when controlled with the effect of baseline psychopathology.
Our findings are inconsistent with the 10-month follow-up of Korean middle-school students (Kim et al., 2009
), which found bullying behaviors to be an independent risk of suicidal behavior and ideation. The discrepancies may stem from differences in study methods, including length of follow-up, age of participants, and differences in bullying identification methods (peer nomination versus self-reports).
While the students who reported only bullying behaviors did not recount other problems at levels meeting the “at-risk” threshold, they were significantly more depressed, suicidal and impaired than other “not at risk” students who did not report bullying behaviors while in high school. Thus, they were not as healthy as students who had not reported bullying behaviors.
Students who experienced bullying behaviors in conjunction with problems warranting their meeting the suicidal-risk threshold in high school were more depressed, had more substance problems, and were more functionally impaired than those at-risk youth not experiencing bullying behaviors. Four years later, the at-risk youth who had experienced bullying behaviors continued to be more functionally impaired. Similarly, Sourander and colleagues (2007)
found that bullies and victims at age 8 who had concurrent psychiatric symptoms had worse long-term outcomes than children who had high levels of psychiatric symptoms but did not bully or were not victimized.
In our earlier study (Gould et al., 2005
) we included bullying behavior in our screening assessment, but available prospective research was not sufficient to guide any clinical recommendations for students reporting this behavior in the absence of other known risk indicators on the suicide screen. To our knowledge, this is the first study to examine the clinical import of bullying behavior in the absence of other psychopathology among high school students for later depression and suicidal ideation/behavior.
The longitudinal design is a major strength of the study, providing a more valid examination of the independent sequelae of bullying behavior than cross-sectional data can provide. However, the study has several limitations. First, since students who were not at risk and not engaged in bullying behavior were not followed, we are unable to determine whether the significant differences between them and those who only reported bullying behaviors in high school continued four years later. However, the remaining contrasts between those who only reported bullying behaviors and the two at-risk groups yielded clinical meaningful differences. Second, the length of follow-up for the 'bully only' group was significantly longer than that of the other two groups. The follow-up of the bully only group was funded by a different grant (approximately 2 years later) than the follow-up protocol of the at risk groups. The growing interest in the impact of bullying prompted the later grant that focused on the sequelae of bullying in the absence of concurrent suicidality, depression, or substance problems. The longer length of follow-up of the bully only group is unlikely to jeopardize our findings or conclusions because this group had even more opportunity to manifest the outcomes of interest, but did not. Third, while we included questions about specific types of victimization (e.g. cyberbullying), we were unable to examine their impact separately due to small sample sizes. Fourth, we do not know about stability of bullying in this sample given that bullying status is only assessed at one point. The at-risk and non-at-risk bullying groups could have differed in stability, history, onset of bullying, or type or quality of bullying behaviors, and that these factors could have been related to outcomes. Fifth, we employed suburban schools with predominantly white populations of limited socioeconomic diversity because the sampling frame was dictated by design considerations of our earlier study (Gould et al., 2005
). As such, the results cannot be generalized to urban, more ethnically or socioeconomically diverse settings. Previous studies reporting on ethnicity and socioeconomic status as factors in bullying behavior have shown inconsistent results (Nansel et al., 2001
; Olweus, 1999
; Seals & Young, 2003
; Veenstra et al., 2005
; Wolke et al., 2001
). Sixth, only sixty-two percent of eligible subjects participated in the study, but we found no demographic or baseline clinical differences between participants and non-participants. Lastly, information about bullying behavior is based only on self reports. Future studies may want to include peer nomination or parent/teacher reports.
In summary, bullying behavior in the absence of depression or suicidality does not warrant inclusion as a stand-alone risk indicator on a suicide screen. However, experiencing bullying behaviors in conjunction with depression or suicidality in high school is indicative of more serious concurrent problems and portends a worse outcome four years later than exhibiting depression or suicidality only. Thus, a clinical recommendation emerging from this study is to include an assessment of bullying behaviors in all suicide screening protocols.