Developmental adaptations to violent environments involve a multitude of cascading effects spanning many levels of analysis from genes to behavior. In this review, we (a) examine the potentiating effects of violence on genetic vulnerabilities and the functioning of neurotransmitter systems in producing both internalizing and externalizing psychopathology; (b) describe implications of violence exposure for brain development, particularly within the hippocampus and prefrontal cortex; and (c) consider the effects of violence on developing human stress and startle responses. This review integrates literatures on the developmental effects of violence among rodents, nonhuman primates, and humans. Many neurobiological changes that are adaptive for survival in violent contexts become maladaptive in other environments, conferring life-long risk for psychopathology.

Parent conflict during infancy may affect rapidly developing physiological regulation. To examine the association between parent conflict and infants' vagal tone functioning, mothers (N = 48) reported levels of parent conflict and their 6-month-old male and female infants' respiratory sinus arrhythmia (RSA) was measured in the still-face paradigm. Higher parent conflict was related to lower RSA at baseline and each episode of the still-face paradigm. Infants in relatively higher conflict families showed attenuated RSA withdrawal in response to mothers' disengagement and attenuated RSA activation when interacting with mothers. Findings suggest atypical RSA regulation and reliance on self-regulation for infants in families with moderate levels of parent conflict. Implications for later development and future research are discussed.

A subset of serotonin (5-HT) pathway polymorphisms has been shown to confer risk for psychological dysfunction, particularly in individuals who experience early adversity. Understanding the developmental processes underlying these Gene × Environment interactions will strengthen the search for risk factors for behavioral dysfunction. We investigated the combined influence of two serotonin pathway polymorphisms and species-atypical, and possibly adverse, rearing (nursery rearing [NR]) on two dimensions of behavioral stress response in infant rhesus macaques. We hypothesized that the experience of NR and possession of both “high-risk” genotypes (genotypes that are thought to confer low 5-HT function) would predict the greatest behavioral stress response to maternal/social separation. Using a matched-pair design, the impact of early experience and the serotonin transporter (rh5-HTTLPR) and monoamine oxidase A (rhMAO-A-LPR) promoter polymorphisms on behavioral reactivity of 136 infant rhesus macaques (90–120 days of age) during a 25-hr social separation/relocation procedure was assessed. Each pair included one infant reared with mother in a large, outdoor field enclosure (field rearing) and one infant reared in a nursery (NR). Pairs were matched for putative gene activity of each polymorphism, sex, age, and weight at testing. Behavioral responses in a “human intruder” test were recorded, and activity and emotional reactivity composites were created to detect different aspects of psychological adaptation to stress. Our hypothesis that high-risk groups would be the most reactive to stress was not entirely borne out. Rh5-HTTLPR × rhMAOA-LPR interactions predicted emotional reactivity and tended to predict behavioral activity scores. Carriers of the two “low-risk” alleles exhibited the lowest behavioral activity, as might be predicted, but carriers of both “high-risk” alleles were two of four genotype groups exhibiting the highest observed Emotional Reactivity. Gene × Gene interactions were exacerbated by the experience of nursery rearing, as predicted, however. Finally, we suggest that genetic or environmental factors may mitigate the risk for behavioral dysregulation illustrated in the patterns of behavioral activity and emotional reactivity displayed by infants.

In this study we investigated the development of the hypothalamic–pituitary–adrenal (HPA) axis in 21 group-living rhesus monkeys infants that were physically abused by their mothers in the first few months of life and in 21 nonabused controls. Cortisol and adrenocorticotropin hormone (ACTH) responses to a corticotropin-releasing hormone (CRH) challenge were assessed at 6-month intervals during the subjects' first 3 years of life. Abused infants exhibited greater cortisol responses to CRH than controls across the 3 years. Abused infants also exhibited blunted ACTH secretion in response to CRH, especially at 6 months of age. Although there were no significant sex differences in abuse experienced early in life, females showed a greater cortisol response to CRH than males at all ages. There were no significant sex differences in the ACTH response to CRH, or significant interactions between sex and abuse in the ACTH or cortisol response. Our findings suggest that early parental maltreatment results in greater adrenocortical, and possibly also pituitary, responsiveness to challenges later in life. These long-term alterations in neuroendocrine function may be one the mechanisms through which infant abuse results in later psychopathologies. Our study also suggests that there are developmental sex differences in adrenal function that occur irrespective of early stressful experience. The results of this study can enhance our understanding of the long-term effects of child maltreatment as well as our knowledge of the development of the HPA axis in human and nonhuman primates.

This study examined how restricted and repetitive behaviors and interests (RRBs) developed over time in a sample of children with autism spectrum disorders (ASD). One hundred ninety-two children referred for a diagnosis of autism at age 2, and 22 children with nonspectrum development disorders were evaluated with a battery of cognitive and diagnostic measures at age 2 and subsequently at ages 3, 5, and 9. Factor analysis of the RRB items on the Autism Diagnostic Interview–Revised revealed two RRB factors at each wave of data collection, one comprising “repetitive sensorimotor” (RSM) behaviors and the other “insistence on sameness” (IS) behaviors. For children with ASD, RSM scores remained relatively high over time, indicating consistent severity, whereas IS scores started low and increased over time, indicating worsening. Having a higher nonverbal intelligence (NVIQ) at age 2 was associated with milder concurrent RSM behaviors and with improvement in these behaviors over time. There was no relationship between NVIQ at age 2 and IS behaviors. However, milder social/communicative impairment, at age 2 was associated with more severe concurrent IS behaviors. Trajectory analysis revealed considerable heterogeneity in patterns of change over time for both kinds of behaviors. These findings are discussed in terms of their implications for our understanding of RRBs in ASD and other disorders, making prognoses about how RRBs will develop in children with ASD as they get older, and using RRBs to identify ASD phenotypes in genetic studies.

This study was designed to examine the nature of object imitation performance in early autism. We hypothesized that imitation would be relatively preserved when behaviors on objects resulted in salient instrumental effects. We designed tasks in which, in one condition, the motor action resulted in a salient, meaningful effect on an object, whereas in the other condition, the same action resulted in a less salient effect because of differing object characteristics. The motor aspects of the tasks did not vary across conditions. Four participant groups of 2- to 5-year-olds were examined: 17 children with early-onset autism, 24 children with regressive onset autism, 22 children with developmental delays, and 22 children with typical development. Groups were matched on nonverbal skills, and differences in verbal development were examined as a moderator of imitative ability. Results revealed an interaction of group by condition, with the combined autism group failing more tasks than the combined comparison groups, and failing more tasks in the less salient condition than in the more salient condition, as hypothesized. Analyses of autism subgroups revealed these effects were primarily because of the regression onset group. Accuracy of motor performance was examined by analyzing errors. Among children passing imitative acts, there were no group differences and no condition effects in the number, type, or pattern of performance errors. Among children passing the tasks, the group with autism did not demonstrate more emulation errors (imitating the goal but not the means) than other groups. There was no evidence that either motor or attentional aspects of the tasks contributed to the poorer imitative performance of the children with autism.

The current meta-analytic study examined the differential impact of maltreatment and various socioeconomic risks on attachment security and disorganization. Fifty-five studies with 4,792 children were traced, yielding 59 samples with nonmaltreated high-risk children (n = 4,336) and 10 samples with maltreated children (n = 456). We tested whether proportions of secure versus insecure (avoidant, resistant, and disorganized) and organized versus disorganized attachments varied as a function of risks. Results showed that children living under high-risk conditions (including maltreatment studies) showed fewer secure (d = 0.67) and more disorganized (d = 0.77) attachments than children living in low-risk families. Large effects sizes were found for the set of maltreatment studies: maltreated children were less secure (d = 2.10) and more disorganized (d = 2.19) than other high-risk children (d = 0.48 and d = 0.48, respectively). However, children exposed to five socioeconomic risks (k = 8 studies, d = 1.20) were not significantly less likely to be disorganized than maltreated children. Overall, these meta-analyses show the destructive impact of maltreatment for attachment security as well as disorganization, but the accumulation of socioeconomic risks appears to have a similar impact on attachment disorganization.

This study examined whether the quality of relationships with foster caregivers was associated with autonomic nervous system reactivity of children during separation and reunion with their foster caregiver. Moreover, effects of early adversity were examined in relation to attachment and autonomic nervous system reactivity. The sample included 60 children between 26 and 88 months of age, who participated with their primary foster caregivers in the Strange Situation. Respiratory sinus arrhythmia and preejection period were measured as indicators of parasympathetic and sympathetic nervous system reactivity, respectively. Attachment quality (ordered/disordered and secure/insecure attachment), was coded on the basis of children's behavior in the Strange Situation using the Cassidy and Marvin coding system. Children with a background of neglect and those with disordered (disorganized–controlling or insecure–other) attachment showed most sympathetic reactivity during the procedure. Moreover, children with disordered attachment showed less vagal regulation (respiratory sinus arrhythmia decreases on separation and increases on reunion) than children with ordered attachment. The findings show that the quality of relationships with current caregivers, and to a lesser extent specific experiences of neglect, may have an impact on children's abilities to regulate emotions in the context of environmental stress and challenges.

The longitudinal associations between maternal parenting behavior and toddler risk with children's emotional and social competence were examined during the transition to kindergarten, in a sample of 253 children. Toddler risk was characterized by early externalizing behavior and poor emotion regulation skills. Given that we were interested in the multiple pathways that may result in emotional and social competence, we examined the interactions among maternal parenting behavior and toddler risk. There were some significant interactions, although the pattern of results was not consistent across all competence outcomes. Maternal parenting behavior was not directly associated with children's emotional and social competence. In some instances, maternal control has differential implications for children's emotional and social competence dependent upon the child's level of early risk and maternal positive parenting. Specifically, maternal control tended to be more detrimental for children's emotional competence during the transition to kindergarten, when children exhibit higher levels of risk. Overall, it appears that there are multiple developmental pathways, depending on child and maternal characteristics that lead to early emotional and social competence.

Teacher-rated trajectories of physical aggression in boys and girls from first through sixth grade were examined using data from the NICHD Study of Early Child Care and Youth Development. In separate analyses, four trajectories were identified in boys and three in girls. Higher levels of aggression in both boys and girls were related to greater sociodemographic risk and higher maternal harshness in the preschool years; lower levels of observed maternal sensitivity during early childhood also predicted higher trajectories of aggression among girls. Trajectory groups also differed on a range of social and academic adjustment outcomes in sixth grade, with the most aggressive children and even moderately aggressive children evidencing some difficulties in adjustment. Patterns and levels of aggression in boys and girls are discussed as are their predictors and consequences.

The present study examined how changes in child Big Five personality characteristics and overreactive parenting during the transition from childhood to adolescence predict adolescent adjustment problems. The sample included 290 children, aged 8–9 years. At three moments, with 2-year intervals, mothers, fathers, and a teacher reported on the child's personality, and mothers and fathers reported on their parenting behavior. At the third measurement moment, mothers, fathers, and children reported on the child's adjustment problems. Rank-order stability of the personality dimensions and overreactive parenting were high. Univariate latent growth models revealed mean-level decreases for extraversion, conscientiousness, and imagination. Mean levels of benevolence, emotional stability, and overreactive parenting were stable. Multivariate latent growth models revealed that decreases in extraversion and emotional stability predicted internalizing problems, whereas decreases in benevolence, conscientiousness, and emotional stability predicted externalizing problems. Increases in overreactive parenting predicted externalizing, but not internalizing problems. The associations were similar for boys and girls. The results indicate that changes in child personality and overreactive parenting during the transition to adolescence are associated with adolescent adjustment problems. Overall, child personality was more important than overreactive parenting, and children were more likely to “act out” than to “withdraw” in reaction to overreactive parenting.

Inconsistencies exist in literature examining hypothalamic–pituitary–adrenal (HPA) axis activity in children and adults who have experienced childhood abuse. Hence, the extent and manner to which childhood abuse may disrupt HPA axis development is largely unknown. To address these inconsistencies, the developmental course of nonstress cortisol in a long-term longitudinal study was assessed at six time points from childhood through adolescence and into young adulthood to determine whether childhood abuse results in disrupted cortisol activity. Nonstress, morning cortisol was measured in 84 females with confirmed familial sexual abuse and 89 nonabused, comparison females. Although dynamically controlling for co-occurring depression and anxiety, hierarchical linear modeling (HLM) showed that relative to comparison females, the linear trend for abused females was significantly less steep when cortisol was examined across development from age 6 to age 30, t (1, 180) = −2.55, p < .01, indicating attenuation in cortisol activity starting in adolescence with significantly lower levels of cortisol by early adulthood, F (1, 162) = 4.78, p < .01. As a more direct test of the attenuation hypothesis, supplemental HLM analyses of data arrayed by time since the disclosure of abuse indicated that cortisol activity was initially significantly higher, t (1, 425) = 2.18, p < .05, and slopes were significantly less steep t (1, 205) = −2.66, p < .01, for abused females. These findings demonstrate how the experience of childhood abuse might disrupt the neurobiology of stress, providing some support for the attenuation hypothesis that victims of abuse may experience cortisol hyposecretion subsequent to a period of heightened secretion.

The purpose of this paper is to evaluate the theory and evidence for the links of parent–child attachment with internalizing problems in childhood and adolescence. We address three key questions: (a) how consistent is the evidence that attachment security or insecurity is linked to internalizing symptoms, anxiety, and depression? (b) How consistent is the evidence that specific forms of insecurity are more strongly related to internalizing symptoms, anxiety, and depression than are other forms of insecurity? (c) Are associations with internalizing symptoms, anxiety, and depression consistent for mother–child and father–child attachment? The current findings are consistent with the hypothesis that insecure attachment is associated with the development of internalizing problems. The links between specific insecure attachment patterns and internalizing problems are difficult to evaluate. Father–child and mother–child attachments have a comparable impact, although there are relatively few studies of father–child attachment. No moderators consistently affect these relations. We also propose two models of how attachment insecurity may combine with other factors to lead to anxiety or depression.

The Diagnostic and Statistical Manual of Mental Disorders lists weight gain or weight loss as a symptom of depression at all ages, but no study of adolescent depression has examined its relation to actual (not just self-reported) weight change. In the current longitudinal study, 215 adolescents provided physical and self-report measures of change in weight, body mass, and body fat over a 4-month time interval. They also completed psychological measures of body dissatisfaction, problematic eating attitudes, and depressive symptoms. The relation between physical measures of weight change and depressive symptoms varied with age. These relations were explained by individual differences in body dissatisfaction, eating attitudes, and behaviors, leading to questions about weight change as a symptom of depression in adolescence.

This multiwave longitudinal study investigated potential transactional and accumulating influences among corumination, interpersonal stressors, and internalizing symptoms among a sample of early and middle adolescents (N = 350; 6th–10th graders). Youth completed self-report measures of corumination at Times 1, 2, and 4, and negative life events, internalizing symptoms (general depressive, specific anhedonic depressive, anxious arousal, general internalizing), and externalizing problems at all four time points (5 weeks between each assessment across 4 months). Results supported hypotheses. First, baseline corumination predicted prospective trajectories of all forms of internalizing symptoms but not externalizing problems. Second, baseline corumination predicted generation of interpersonal-dependent, but not interpersonal-independent or noninterpersonal stressors. Third, interpersonal-dependent events partially mediated the longitudinal association between baseline corumination and prospective internalizing symptoms. Fourth, a transactional, bidirectional set of associations was supported in that initial internalizing symptoms and stressors predicted later elevations in corumination, and in turn, corumination predicted later symptoms through the mediating role of interpersonal stressors to complete both streams in the transactional chain of influence. Fifth, girls and older adolescents exhibited higher corumination, but neither age nor sex moderated any associations. These findings are discussed within a transactional, developmental cascade model.