Gene-environment interplay between peer rejection and depressive behavior in children

BACKGROUND

Genetic risk for depressive behavior may increase the likelihood of exposure to environmental stressors (gene-environment correlation, rGE). By the same token, exposure to environmental stressors may moderate the effect of genes on depressive behavior (gene-environment interaction, GxE). Relating these processes to a peer-related stressor in childhood, the present study examined (1) whether genetic risk for depressive behavior in children is related to higher levels of rejection by the peer group (rGE) and (2) whether peer rejection moderates the effect of genetic factors on children's depressive behavior (GxE).

METHODS

The sample comprised 336 twin pairs (MZ pairs = 196, same-sex DZ pairs = 140) assessed in kindergarten (mean age 72.7 months). Peer acceptance/rejection was measured via peer nominations. Depressive behavior was measured through teacher ratings.

RESULTS

Consistent with rGE, a moderate overlap of genetic effects was found between peer acceptance/rejection and depressive behavior. In line with GxE, genetic effects on depressive behavior varied across levels of peer acceptance/rejection.

CONCLUSIONS

An increased genetic disposition for depressive behavior is related to a higher risk of peer rejection (rGE). However, genes play a lesser role in explaining individual differences in depressive behavior in rejected children than in accepted children (GxE).

Peer victimization as a predictor of depression and body mass index in obese and non-obese adolescents

BACKGROUND

The current study examined the pathway from peer victimization to depressive symptoms and body mass index (BMI) as mediated by self-concept for physical appearance in both obese and non-obese adolescents. It was thought that this pathway would be particularly important for obese adolescents because, compared to non-obese adolescents, they are at risk for being victimized and because the victimization would be more likely to lead to lower self-concept.

METHOD

Utilizing data from the National Longitudinal Survey of Children and Youth, the current study examined self-reports of peer victimization, self-concept for physical appearance, depressive symptoms, height, and weight in 1,287 adolescents at three time periods over four years starting when the participants were between the ages of 12 and 13.

RESULTS

For non-obese adolescents, victimization did not predict changes in depressive symptoms and body mass index (BMI) four years later. For obese females, the mediated pathway was found from victimization to self-concept to both depressive symptoms and increases in BMI. For obese males, the findings were more complicated. In this group, the mediated pathway was found from victimization to self-concept to decreases in BMI, but a mediated pathway was not found for depressive symptoms.

CONCLUSIONS

The current study suggests that a risk-factor for being victimized, such as obesity, may play an important role in the long-term effects of victimization by making it more likely that the adolescent will be victimized over the long term but also that victimization can reinforce the negative self-perceptions that the adolescent already has. It is important to go beyond using obesity as a predictor of long-term adjustment and examine the processes and experiences of obese individuals that might more directly cause depression or changes in health.

Linkages between children's and their friends' social and physical aggression: evidence for a gene-environment interaction?

Based on a sample of 406 seven-year-old twins, this study examined whether exposure to friends' social or physical aggression, respectively, moderates the effect of heritability on children's own social and physical aggression. Univariate analyses showed that children's own social and physical aggression were significantly explained by genetic factors, whereas friends' social and physical aggression represented "true" environmental factors that were unrelated to children's genetic dispositions. Multivariate analyses further suggested a possible gene-environment interaction in the link between friends' and children's physical aggression but not in the link between friends' and children's social aggression. Instead, friends' social aggression was directly related to children's social aggression, in addition to genetic effects on this behavior. Theoretical and practical implications of these results are discussed.

Friendship moderates prospective associations between social isolation and adjustment problems in young children

This longitudinal study investigated prospective links between social isolation and adjustment problems among 166 (77 girls, 89 boys) Finnish children ages 7 to 9. Peer nominations for social engagement and self-reports of internalizing and externalizing problems were collected in the spring of the 1st and 2nd grade. Friendship moderated prospective associations between peer and adjustment variables. Among friended children, there were no prospective associations between social isolation and either internalizing or externalizing problems. Among unfriended children, initial social isolation was positively linked to subsequent increases in internalizing and externalizing problems, and initial internalizing and externalizing problems predicted subsequent increases in social isolation. The findings suggest that friendship buffers against the adverse consequences associated with being isolated and presenting adjustment difficulties.

Relationships with mothers and peers moderate the association between childhood sexual abuse and anxiety disorders

OBJECTIVE

The objective of the current study was to assess whether relationships with mothers and peers moderate the association between childhood sexual abuse (CSA) and anxiety disorders. That is, positive and supportive experiences were expected to minimize the effects of CSA whereas nonsupportive experiences were expected to magnify them.

METHOD

Participants from a large, stratified, multistage-area, probability community sample provided retrospective reports of CSA and childhood relationships with mothers and peers and a modified version of the Composite International Diagnostic Interview produced life-time psychiatric diagnoses of four non-phobic anxiety disorders after the age of 18.

RESULTS

Utilizing multiple-regressions, a two-way interaction found that for those reporting low levels of friendship quality there was a stronger link between CSA and the number of diagnosed anxiety disorder than those reporting high levels of friendship quality. In addition a three-way interaction found that those reporting to have no friends and a low quality mother-child relationships had the strongest association between CSA and the number of diagnosed anxiety disorders, while those reporting to have many friends and a high quality relationship had the weakest association.

CONCLUSIONS

The findings from the current study suggest that relationships with friends and parents may play an important role in understanding the links between childhood sexual abuse and later anxiety disorders and that these relationships may also be important sources of protection against the negative effects of childhood sexual abuse.

What aspects of peer relationships are impaired in children with attention-deficit/hyperactivity disorder?

Participants included 165 children with attention-deficit/hyperactivity disorder (ADHD; 130 boys, 35 girls) and their 1,298 same-sex classmates (1,026 boys, 272 girls) who served as raters. For each child with ADHD, a child of the same sex was randomly selected from the same classroom to serve as a comparison child, which yielded 165 dyads. Consistent with predictions, contrasted with the comparison children, those with ADHD were lower on social preference, higher on social impact, less well liked, and more often in the rejected social status category; they also had fewer dyadic friends. When liking ratings that children made versus received were examined, children with ADHD had less positive imbalance and greater negative imbalance relative to comparison children. Analyses that considered the types of peers who chose children with ADHD as friends or nonfriends demonstrated that children with ADHD were nominated as nonfriends by children of higher social preference and who were better liked by others.

Peer relationships and psychopathology: markers, moderators, mediators, mechanisms, and meanings

As the study of peer relations has grown and developed, it has gained a prominent position in the understanding of developmental process and psychopathology. During its development, research in peer relations has moved from a more undifferentiated, global state to a state of increased articulation and complexity. This introductory essay attempts to provide examples of five models that reflect the state of the art in peer relation research: Markers, moderators, mediators, mechanisms, and meanings. Examples from the papers in the special issue and research from the general field of peer relations are used to illustrate these five approaches to the study of peer relations and developmental psychopathology.

Peer-assessed outcomes in the multimodal treatment study of children with attention deficit hyperactivity disorder

Peer-assessed outcomes were examined at the end of treatment (14 months after study entry) for 285 children (226 boys, 59 girls) with attention deficit hyperactivity disorder (ADHD) who were rated by their classmates (2,232 classmates total) using peer sociometric procedures. All children with ADHD were participants in the Multimodal Treatment Study of Children with ADHD (MTA). Treatment groups were compared using the orthogonal treatment contrasts that accounted for the largest amount of variance in prior MTA outcome analyses: Medication Management + Combined Treatment versus Behavior Therapy + Community Care; Medication Management versus Combined Treatment; Behavior Therapy versus Community Care. There was little evidence of superiority of any of the treatments for the peer-assessed outcomes studied, although the limited evidence that emerged favored treatments involving medication management. Post hoc analyses were used to examine whether any of the four treatment groups yielded normalized peer relationships relative to randomly selected-classmates. Results indicated that children from all groups remained significantly impaired in their peer relationships.

Height and social adjustment: are extremes a cause for concern and action?

OBJECTIVE

Growth hormone treatment of hormone-sufficient short youths is predicated on the belief that short stature is associated with social problems with peers. This study assessed peer relations and social adjustment as a function of height in a community sample.

METHODS

A cross-sectional study was conducted at 1 public school district in Western New York of students of both genders who attended grades 6 to 12 (N = 956). Target groups included participants of short stature (height <or=-1.6 standard deviation, ie, <or=5th percentile for age- and gender-adjusted population norms; n = 68) and tall stature (>or=1.6 standard deviation; >or=95th percentile; n = 58) and classmates of average height (between the 25th and 75th percentiles; n = 123) used for within-class comparisons. All remaining unclassified classmates (n = 704) also provided data. Self- and peer-rated assessment of social reputation and social acceptance was measured.

RESULTS

Minimal effects of height on measures of social functioning were detected despite substantial statistical power. We detected no significant relationships between height and measures of friendship, popularity, or reputation with peers. Findings did not vary by gender of participant, by peer- or self-report, or by whether data from the entire sample were used or target groups were contrasted with comparison participants. Shorter students were perceived by peers to be younger than their age. This influence was restricted to lower grades and did not have an impact on measures of social acceptance or reputation with peers.

CONCLUSIONS

Extremes of stature in the general population-either short or tall-have minimal detectable impact on peer perceptions of social behavior, friendship, or acceptance. Findings are not supportive of the need to intervene a priori because of the potential risk of negative stature-related social sequelae. Furthermore, if problems with peer relationships are identified among short or tall youths, then factors other than stature should be considered as etiologically important.

Interpersonal influence and disordered eating behaviors in adolescent girls: the role of peer modeling, social reinforcement, and body-related teasing

This study investigated the association between interpersonal relationships, eating behaviors, and body esteem in a sample of adolescent girls. Participants included 876 girls who completed questionnaires regarding body esteem, eating behavior, peer pressure, and interpersonal relationships. Peer pressure was a strong predictor of eating behavior and body esteem after controlling for interpersonal variables. High externalized self-perceptions, self-reported teasing, and attributions about the importance of weight and shape for popularity and dating were important predictors of both body esteem and eating behavior. Also, girls who were nominated as popular by peers were more likely to engage in disordered eating and have lower body esteem. Results highlight the need for eating disorder prevention at the level of the peer group. Programs should focus on decreasing pressure to be thin, acceptance by peers for attributes other than appearance, and combating weight- and shape-related teasing within the school system.

Choosing or Being Chosen by Aggressive–Disruptive Peers: Do They Contribute to Children's Externalizing and Internalizing Problems?

The goal of this study was to investigate the extent to which aggressive-disruptive peers contribute to the development of externalizing and internalizing problems in children, while controlling for children's own behavior. We examined 2 sets of peers: (1) those that the child nominated as friends, and (2) those that nominated the child as a friend. The participants were 236 boys and girls attending 3rd to 5th grade at the beginning of the study, who were followed over a period of 2 years. Results showed that choosing more aggressive peers on the nomination procedure was associated with more externalizing problems and self-reported depressive symptomatology over time. On the other hand, being liked by more aggressive children generally was not associated with elevated externalizing or internalizing problems.

Understanding adolescent worry: the application of a cognitive model

The relationship between worry and 4 cognitive variables, intolerance of uncertainty, positive beliefs about worry, negative problem orientation, and cognitive avoidance, was examined in an adolescent sample of 528 boys and girls aged 14-18. The participants completed questionnaires assessing worry, somatic anxiety symptoms, and the variables mentioned above. The results show that (a) intolerance of uncertainty, positive beliefs about worry, and negative problem orientation each account for a significant amount of variance in adolescent worry scores in the multiple regression, and (b) the discriminant function derived from the 4 variables is effective in classifying moderate and high worriers into their respective groups (72.8% correct classification). Furthermore, analyses demonstrate that intolerance of uncertainty has the strongest association with worry scores and is the most important variable in discriminating between moderate and high adolescent worriers. These results suggest that intolerance of uncertainty plays a key role in our understanding of adolescent worry.

Developmental profiles of peer social preference over the course of elementary school: associations with trajectories of externalizing and internalizing behavior

Using a new longitudinal clustering technique, this study aimed to (a) empirically identify groups of children with distinct longitudinal profiles of peer social preference during elementary school; (b) compare these groups regarding their longitudinal pattern of classification into J. D. Coie, K. A. Dodge, and H. Coppotelli's (CDC; 1982) sociometric categories; and (c) compare these groups regarding their longitudinal trajectories of antisocial, hyperactive, and anxious behavior. Based on 299 children, 3 groups were identified: a stable popular group, a stable average group, and an unpopular group whose social preference decreased over time. Each of the groups showed considerable overlap over time with their closest corresponding CDC category (popular, average, rejected). Growth curve analyses showed that externalizing and internalizing behavior generally decreased over time, but overall means and the rates of decrease differed in the 3 groups.