Peer Victimization Predicts Sleep Problems in Early Adolescence

Abstract

This study examined the prospective association between peer victimization and subjective sleep quality among typically developing early adolescents. At Time 1 (T1), participants included 123 youth (50% boys; $\bar{X}$ age = 12.03 years; 58.5% European American, 35% African American), along with one parent and teacher. Youth, parents, and teachers reported on youth’s experiences of peer victimization at T1. Youth reported on sleep quality at T1 and T2 (10 months later). Results from regression analyses revealed that youth-reported, but not parent- or teacher-reported, peer victimization predicted poorer sleep quality over time. Findings provide evidence that experiences of peer victimization can have a negative impact on youth’s sleep quality over time.

Keywords

peer victimization sleep early adolescence

Inadequate and poor-quality sleep are common in early adolescence with approximately 50% of young adolescents receiving less than the recommended amount of sleep and approximately 22% to 32% reporting sleep problems (e.g., difficulty falling/staying asleep; National Sleep Foundation, 2006, 2014). In addition, short sleep duration and sleep problems (assessed via youth and/or parent reports, actigraphy) can undermine mental health, specifically anxiety and depression, as well as physical health and daily functioning among youth, concurrently and over time (for a review, see Shochat, Cohen-Zion, & Tzischinsky, 2014). Sleep is affected by biological, social, and psychological influences. For instance, during early adolescence, circadian phase delay associated with puberty (Sadeh, Dahl, Shahar, & Rosenblat-Stein, 2009), potential environmental impediments (e.g., school start times, use of electronic technology; Borlase, Gander, & Gibson, 2013), and stressful experiences (Sadeh & Gruber, 2002) may influence sleep patterns and/or quality. During early adolescence in particular, rates of peer problems, such as peer victimization, increase (J. Wang, Iannotti, & Nansel, 2009), which may not only affect youth’s mental health (e.g., Reijntjes et al., 2011; Reijntjes, Kamphuis, Prinzie, & Telch, 2010) but also interfere with their sleep. Indeed, an emerging line of work has shown that peer victimization is associated with sleep problems among children and adolescents (for a meta-analysis, see van Geel, Goemans, & Vedder, 2016). This association may be due, in part, to the emotional distress induced by peer victimization (Morrow, Hubbard, Barhight, & Thomson, 2014; Nishina & Juvonen, 2005), which can disrupt sleep, consistent with the vigilance-arousal framework (Dahl, 1996).

The aforementioned meta-analysis revealed that subjective reports of peer victimization were concurrently associated with subjective sleep problems among children and adolescents, such that the odds of experiencing sleep problems were higher among those who experienced peer victimization compared with those who did not (odds ratio = 2.21, 95% confidence interval = [2.01, 2.44], I² = 93.07; van Geel et al., 2016). However, this meta-analysis also revealed that the work in this young literature has been limited to single-informant, cross-sectional designs as well as single-item assessments of peer victimization and/or sleep.

A few studies have examined prospective associations between peer victimization and sleep problems. Chronic observed and self-reported peer victimization between the ages of 5 and 16 were associated with more subjective sleep problems in adolescence (Biebl, DiLalla, Davis, Lynch, & Shinn, 2011). Similarly, self-reported peer victimization was associated with later self-reported sleep problems (e.g., sleep deficits, sleep/wake problems) among middle school (Lepore & Kliewer, 2013) and high school (Herge, La Greca, & Chan, 2016) students. Across the aforementioned studies, the prediction of change in adolescent sleep over time was not examined (i.e., earlier sleep was not controlled when predicting later sleep). Only one known study has revealed links between self-reported victimization and later subjective sleep problems, controlling for earlier levels of sleep problems, in a sample of middle schoolers (Sosnowski, Kliewer, & Lepore, 2016), but victimization was assessed generally, as perpetrated by anyone (not just peers; Sosnowski et al., 2016). Thus, it remains unclear whether peer victimization, specifically, predicts increasing sleep problems over time.

Toward advancing this literature, we conducted a conservative test of the prospective association between peer victimization and sleep quality over time, controlling for initial sleep quality. We accounted for earlier levels of sleep quality as well as anxiety and depressive symptoms, known correlates of peer victimization (Reijntjes et al., 2010) and sleep quality (Shochat et al., 2014). Controlling for anxiety and depressive symptoms allowed a more stringent test of the study’s aim, reducing the potential confounds of internalizing symptoms and related negative cognitive biases (e.g., Mathews & MacLeod, 2005) that may underlie youth reports of both peer victimization and sleep quality. Further, expanding knowledge beyond subjective reports of peer victimization, we investigated the prospective link between peer victimization and sleep quality across youth, parent, and teacher reports of peer victimization. Youth, parents, and teachers have related but not redundant perspectives on peer victimization, and multiple informants are recommended for a more complete assessment of peer victimization (Ladd & Kochenderfer-Ladd, 2002). Including multiple informants may clarify the robustness of the association between peer victimization and sleep quality, as well as the similar or particular predictive strength of each perspective.

Consistent with established conceptual frameworks (e.g., vigilance-arousal framework; Dahl, 1996) as well as findings from prior studies (Biebl et al., 2011; Herge et al., 2016; Sosnowski et al., 2016; van Geel et al., 2016), we hypothesized that peer victimization would be associated with poorer sleep quality over time, controlling for initial sleep quality. Because investigations linking peer victimization and sleep have relied primarily on self-reports of peer victimization, we had no a priori hypotheses regarding potential differences in the associations by informants of peer victimization.

Method

Participants

At Time 1 (T1), participants included 123 fifth- and sixth-grade students ( $\bar{X}$ age = 12.03 years, SD = 0.64; 50% boys), one parent (82% biological mothers, 67% married, 100% participation), and one teacher (81% reports obtained) per child. The sample of youth included 58.5% European Americans, 35% African Americans, and 6.5% of other races/ethnicities. The modal annual family income was between US$35,001 and US$50,000; 21% reported an income of less than US$20,000, and 24% reported an income of greater than US$75,000. At T1, participants without teacher data were more likely to be ethnic minorities (χ² = 9.21, p < .01), from lower income households (t = −2.64, p < .01), and report lower quality sleep at T1 (t = −2.34, p < .05). At Time 2 (T2), participants included 99 adolescents ( $\bar{X}$ age = 12.78 years, SD = 0.63; 48% boys). There were no differences between participants who did and did not participate at T2 on demographic or primary study variables.

Procedures

Data for the present study come from a larger project, and thus, only pertinent procedures are described (for additional details see Erath, Bub, & Tu, 2016). The short-term longitudinal design of the present study involved two waves of data collection, spaced approximately 10 months apart. For T1, participants were recruited in two cohorts (approximately 60 participants per cohort), separated by 1 year (Cohort 1 data collected from 2010-2011, Cohort 2 data collected from 2011-2012). Flyers were sent home with fifth- and sixth-grade students at five elementary schools in the southeastern United States during the spring. We distributed letters to approximately 28 classrooms across the five elementary schools for each cohort. Exclusion criteria included youth with diagnoses of pervasive developmental disorders, intellectual disability, or social phobia due to the nature of the laboratory activities of the larger study.

At T1, parents who responded to the school flyers in the spring were given information about the study and were scheduled for a research visit (occurring during the summer) over the phone. Parental permission to contact teachers was obtained in the spring, and consent was obtained from participating teachers who completed questionnaires before the end of the school year. In the summer (before youth transitioned to middle school), youth and parents visited the research laboratory (for approximately 2 hours). Consent and assent to participate were obtained and youth and parents completed questionnaires.

At T2, participants were re-contacted during the spring of youth’s first year in middle school for a follow-up visit. Parents and youth completed questionnaires and provided the name of the teacher who knew the student best to report on youth’s peer adjustment. Teachers were contacted to participate, and they completed questionnaires in the spring. At both waves, youth, parents, and teachers were compensated monetarily for their time and effort (US$60 each for youth and parents, US$30 for teachers). All study procedures were approved by the university’s institutional review board.

Measures

Peer victimization (T1)

Youth, parents, and teachers reported on peer victimization using well-validated scales. Youth completed seven items from the Social Experiences Questionnaire (e.g., “How often do you get pushed or shoved by other peers at school?” and “How often have other kids said mean things about you to keep other people from liking you?”; Crick & Grotpeter, 1996), rated on a 5-point scale (1 = almost never to 5 = almost always). Internal consistency was high (α = .85). In addition, parents completed seven items that are commonly used to assess children’s peer victimization experiences (e.g., “Other children try to hurt my child’s feelings by excluding him or her”; Ladd & Kochenderfer-Ladd, 2002; Schwartz, Farver, Chang, & Lee-Shin, 2002), rated on a 5-point scale (1 = never to 5 = almost always). This measure had high internal consistency (α = .94). Finally, teacher-reported peer victimization was assessed with six items from the Social Behavior Rating Scale (e.g., “Other children hit or push this child” and “Other children tease or make fun of this child”; Schwartz et al., 2002), rated on a 5-point scale (1 = almost never true to 5 = almost always true). Internal consistency was high (α = .91). For each measure, items were averaged; higher scores reflect higher levels of peer victimization.

Sleep quality (T1 and T2)

Youth completed four items from the Sleep/Wake Problems Scale of the Sleep Habits Survey (Wolfson & Carskadon, 1998), rated on a 5-point scale (0 = never to 4 = every day/night). The four items were as follows: “In the last 2 weeks, how often have you (a) felt satisfied with your sleep, (b) awakened too early in the morning and couldn’t get back to sleep, (c) had an extremely hard time falling asleep, and (d) had a good night’s sleep. Negatively valenced items were reverse-scored such that higher scores reflect higher-quality sleep. The internal consistency of the sleep quality composite used in the present study was acceptable (αs = .61 and .72 at T1 and T2, respectively). Given the relatively low reliability, factor analyses were conducted and revealed that these four items yielded moderate to high factor loadings on a single construct of sleep quality at T1 (loadings ranged from .29 to .58, ps < .01) and T2 (loadings ranged from .41 to .82, ps < .001).

Control variables (T1)

Several variables were included as covariates given their associations with peer victimization and/or sleep, including youth gender (coded 0 = male, 1 = female), race/ethnicity (coded 0 = European American, 1 = minority), annual household income (1 = <US$10,000 to 6 = >US$75,000), and anxiety and depressive symptoms. Youth completed the Revised Children’s Manifest Anxiety Scale (28 items; Reynolds & Richmond, 1978), which assesses whether youth felt anxious in various situations (0 = no, 1 = yes). Two items about sleep problems were removed (α = .86). Youth also reported on depressive symptoms using the Children’s Depression Inventory (26 items; Kovacs, 1985). Each item included three possible responses (0 = absence of symptom to 2 = presence of symptom). One item regarding suicidal ideation was not included in the survey, and two items about sleep problems were removed (α = .79). For anxiety and depressive symptoms, higher scores reflect higher levels of internalizing symptoms.

Plan of Analysis

Data were checked for skewness and outliers; skewness scores were within the acceptable range (<1.28; Kline, 2005). The distribution of all peer victimization variables had a slight positive skew, consistent with broader literature (e.g., J. Wang et al., 2009; W. Wang et al., 2014). One score of parent-reported peer victimization exceeded 4 SDs, but sensitivity analyses revealed nearly identical results between the original analyses (reported) and those in which the outlier was winsorized (e.g., recoded as the next highest score) or removed. Next, regression analyses were conducted to examine the association between T1 peer victimization and T2 sleep quality. First, covariates, including T1 sleep quality, gender, race/ethnicity, and annual household income, as well as youth anxiety and depressive symptoms, were entered in the model, followed by peer victimization. Separate regression models were fitted by informant of peer victimization.

Results

Preliminary Analyses

Descriptive statistics and correlations among primary study variables are reported in Table 1. Youth- and parent-reported peer victimizations were positively correlated, as were parent- and teacher-reported peer victimization. Further, youth- and parent-reported victimization were correlated with lower levels of youth-reported sleep quality at T1; only youth-reported peer victimization was linked with lower sleep quality at T2. Sleep quality was moderately stable over time. Among control variables, higher levels of annual household income were correlated with lower levels of youth-reported peer victimization and higher levels of T1 sleep quality. Anxiety and depressive symptoms were positively correlated with youth-, parent-, and teacher-reported peer victimization and negatively correlated with sleep quality at T1 and T2. Results from t tests revealed no differences across study variables by gender or race/ethnicity.

Table 1.

Descriptive Statistics and Correlations Among Covariates, Peer Victimization, and Sleep Quality.

	1	2	3	4	5	6	7	8
1. T1 Income	—
2. T1 Anxiety	−.20*	—
3. T1 Depressive symptoms	−.28**	.74***	—
4. T1 Youth-reported PV	−.22*	.64***	.56***	—
5. T1 Parent-reported PV	−.13	.47***	.39***	.51***	—
6. T1 Teacher-reported PV	−.19	.23*	.23*	.18	.40***	—
7. T1 Sleep quality	.20*	−.49***	−.60***	−.44***	−.31*	−.09	—
8. T2 Sleep quality	.10	−.30**	.31**	−.46***	−.20	−.11	.42***	—
X– (SD)	4.13 (1.55)	0.29 (0.22)	0.22 (0.20)	2.03 (0.89)	1.95 (0.73)	1.54 (0.67)	2.81 (0.86)	2.72 (0.91)
Range	1-6	0-0.96	0-0.75	1-4.43	1-5	1-3.67	0.25-4	0-4

Note. T1 = data collected at Time 1; PV = peer victimization; T2 = data collected at Time 2.

p < .05. **p < .01. ***p < .001.

Linking Peer Victimization With Change in Sleep Quality

As shown in Table 2, results from regression analyses revealed that, among covariates, only T1 sleep quality was associated with T2 sleep quality. Further, central to our investigation, youth-reported, but not parent- or teacher-reported, peer victimization was associated with lower levels of sleep quality over time. Youth-reported peer victimization explained 7.9% of the unique variance in T2 sleep quality, above and beyond covariates.

Table 2.

Regression Coefficients of the Association Between Peer Victimization and Sleep Quality.

	T2 sleep quality
	B (SE)	β
T1 Control variables
Gender	.09 (.17)	.05
Race/ethnicity	.04 (.20)	.02
Income	.003 (.07)	.01
Anxiety	−.54 (.60)	−.13
Depressive symptoms	.02 (.70)	.003
Sleep quality	.36 (.12)**	.34**
R²	17.5%
T1 Predictors
Youth-reported peer victimization	−.38 (.12)**	−.37**
R²	25.4%
Parent-reported peer victimization	−.01 (.13)	−.01
R²	17.6%
Teacher-reported peer victimization	−.10 (.14)	−.07
R²	18.1%

Note. Youth-, parent-, and teacher-reported peer victimization were tested in separate models and corresponding R² refers to the total R² of each model with the same set of control variables. Gender coded 0 = boys, 1 = girls; race/ethnicity coded 0 = European American, 1 = minority. T2 = data collected at Time 2; T1 = data collected at Time 1.

p < .01.

Discussion

Utilizing a multi-informant, longitudinal design, the present study used a conservative model to examine the association between peer victimization and sleep quality during early adolescence. Supportive of our hypothesis, we found that youth-reported peer victimization was associated with lower levels of sleep quality over approximately 1 year, even after controlling for autoregressive effects. Findings from the present study corroborate emerging evidence of the association between higher levels of self-reported peer victimization and concurrent and later self-reported poor sleep quality (e.g., Herge et al., 2016; Lepore & Kliewer, 2013; van Geel et al., 2016). Findings are also consistent with a prior study that documented the longitudinal link between victimization (broadly defined, including adult-child victimization) and increases in sleep problems 6 months later (i.e., controlling for earlier levels of sleep quality; Sosnowski et al., 2016). The present study offers new evidence that youth-reported peer victimization is longitudinally associated with poorer sleep quality, such that the association is evident even after accounting for earlier levels of sleep quality and internalizing symptoms. By accounting for anxiety and depressive symptoms, this study demonstrates that the association between youth-reported peer victimization and later sleep quality is not explained by initial internalizing symptoms or related negative cognitive biases (e.g., Mathews & MacLeod, 2005).

A prospective association between peer victimization and poorer sleep quality emerged for youth-reported, but not parent- or teacher-reported, peer victimization. Including parent- and teacher-reported peer victimization provides an important contribution to the literature, which has primarily utilized self-reports of peer victimization (e.g., van Geel et al., 2016). Youth’s subjective experiences of peer victimization are generally related to parent and teacher reports of peer victimization, but cross-informant associations are modest to moderate (in the present study and broader literature; for example, Holt, Kantor, & Finkelhor, 2008; Løhre, Lydersen, Paulsen, Mæhle, & Vatten, 2011), and only youth’s subjective experiences were prospectively associated with poorer sleep quality in the present study. One possibility is that youth reports reflect the full range of peer victimization experiences—from subtle to severe and from relational to overt, whereas parent and teacher reports rely on more observable instances of peer victimization (e.g., overt, extreme) or instances disclosed by youth (e.g., Pouwels, Souren, Lansu, & Cillessen, 2016). Future research that better distinguishes the intensity and forms of peer victimization may help clarify the stronger predictive power of youth reports compared with parent or teacher reports.

This study provides strong evidence for the link between peer victimization and sleep quality over time, which could inform future investigations of sleep as a potential mechanism through which peer victimization may be associated with youth mental health. Such work would extend this young literature, which has documented some emerging evidence that general victimization is indirectly linked with externalizing problems via adolescent sleep problems (Sosnowski et al., 2016). In addition to the potential explanatory function that sleep may have in the link between peer victimization and youth adjustment outcomes, one study identified sleep as a moderator of the association linking peer victimization with mental health among older adolescents (Tu, Erath, & El-Sheikh, 2015). Specifically, better adolescent-reported sleep quality served as a protective buffer against internalizing symptoms at high levels of adolescent-reported peer victimization (Tu et al., 2015). Future work considering the role of sleep as a mechanism or moderator in the context of peer victimization would contribute to knowledge regarding other ways to address the negative effects of peer victimization.

Several limitations of the current study point to additional directions for future research. First, our community-based sample may have yielded results that would not generalize to a higher-risk sample. Investigations with youth who experience more severe or chronic peer problems would provide greater insight into the extent of sleep problems over time among youth at greater risk. It is possible there may have been selection bias based on the recruitment procedures. Specifically, we recruited parents of students via informational letters that invited them to participate in a study about children’s responses to peer relationship challenges. However, given the typical mean levels and relatively wide range of scores on the measures of peer victimization, it is possible that the recruitment method equally encouraged some parents of students with social difficulties to participate and discouraged other parents. Second, although our measure of sleep quality extended prior literature examining single-item sleep assessments (van Geel et al., 2016), our measure did not have high internal consistency and we did not distinguish multiple dimensions of sleep (e.g., duration, quality). Although subjective self-reports of sleep are sensitive to individual differences in needs for sleep, examining multiple sleep parameters and utilizing various methodologies (e.g., actigraphy, polysomnography, sleep diaries) are warranted for a stronger assessment of the sleep construct (Sadeh, 2015), and would reduce common informant bias in models examining youth-reported peer victimization. Third, although we accounted for general internalizing symptoms, it is still possible that emotional distress or negative emotions associated specifically with experiences of peer victimization serve as mechanisms through which peer victimization is associated with poorer sleep quality, although this was not assessed or tested in the present study. Finally, there is also evidence in the literature regarding gender differences in youth sleep duration and quality (although somewhat mixed; Olds, Blunden, Petkov, & Forchino, 2010; Organek et al., 2015), as well as experiences of and responses to peer victimization (e.g., Guyer, Caouette, Lee, & Ruiz, 2014; Rose & Rudolph, 2006). However, mean-level gender differences did not emerge in the present study, and we did not have adequate power to test for group differences in the models. Yet, the examination of potential gender differences in the association between peer victimization and sleep is an important future direction.

Despite the limitations, the present study employed other rigorous methods, namely a longitudinal design with multiple informants of peer victimization. Findings from this study indicating a longitudinal link between peer victimization and sleep provide insight into one potential avenue (reducing peer victimization) through which to promote better sleep quality among youth. Further, study results highlight the importance of youth perceptions of peer victimization, above and beyond internalizing symptomatology. The present study may also contribute to the broader literature by identifying another potential target (e.g., sleep) that could have a direct and/or indirect effect on youth mental health in the context of peer victimization.

Footnotes

Acknowledgements

We thank study participants, school personnel, and lab staff for data collection and preparation.

Authors’ Note

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Science Foundation.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by a grant from the National Science Foundation (BCS 0921271) awarded to Stephen A. Erath.

Author Biographies

Kelly M. Tu, PhD, is affiliated with the Department of Human Development and Family Studies at the University of Illinois at Urbana-Champaign. Her research focuses on associations among parent-child relationships, behavioral and physiological responses to stress, experiences of stress in social and academic contexts, and well-being among children and adolescents.

Clayton W. Spencer, MS, is affiliated with the Department of Human Development and Family Studies at Auburn University. His research focuses on social stress and sleep processes among children and adolescents.

Mona El-Sheikh, PhD, is Leonard Peterson & Co., Inc., Professor in the department of Human Development & Family Studies at Auburn University. Her research focuses on associations among socioeconomic adversity, family risk and child/adolescent outcomes including psychological adjustment, autonomic nervous system activity, and sleep processes.

Stephen A. Erath, PhD, is affiliated with the Department of Human Development and Family Studies at Auburn University. His research focuses on social stress in childhood and adolescence, including the experience of stress in family and peer contexts, outcomes of exposure to significant social stress, and vulnerability and protective factors in the context of social stress.

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