Adolescent brain development: a period of vulnerabilities and opportunities. Keynote address

Characteristics, correlates, and outcomes of childhood and adolescent depressive disorders

Depressive illness beginning early in life can have serious developmental and functional consequences. Therefore, understanding the disorder during this developmental stage is critical for determining its etiology and course, as well as for deveiopinq effective intervention straieqies. This paper summarizes current knoviedqe reqardinq the etiology, phenomenoiogy, correlates, natural course, and consequences of unipolar depression in children and adolescents. Using adult depression as a framevork, the unique aspects of childhood and adolescence are considered in order to better understand depression within a developmental context. The data suggest that the clinical presentation, correlates, and natural course of depression are remarkably similar across the lifespan. There are, however, important developmental differences. Specifically, the familial and psychological context in which depression develops in youngsters is associated with variability in the frequency and nature of depressive symptoms and comorbid conditions among children and adolescents. Maturational differences have also been identified in the neurobiological correlates of depression. These developmental differences may be associated with the observed variability in clinical response to treatment and longitudinal course. Characterization of the developmental differences will be helpful in developing more specific and effective interventions for youngsters, thereby allowing them to reach their full potential as adults.

Interventions for suicidal youth: a review of the literature and developmental considerations

Suicidal behavior is developmentally mediated, but the degree to which interventions for suicidal behaviors have been developmentally tailored has varied widely. Published controlled studies of psychosocial treatment interventions for reducing adolescent suicidal behavior are reviewed, with a particular emphasis on the developmental nuances of these interventions. In addition, developmental considerations important in the treatment of suicidal adolescents are discussed. There are insufficient data available from controlled trials to recommend one intervention over another for the treatment of suicidal youth, but interventions that are sensitive to the multiple developmental contexts have potential for greater effectiveness in reducing adolescent suicidal behavior.

Developmental changes in hypothalamus-pituitary-adrenal activity over the transition to adolescence: normative changes and associations with puberty

Home baseline and laboratory stressor (Trier Social Stress Test for Children) measures of salivary cortisol were obtained from 82 participants (40 girls) aged 9, 11, 13, and 15 years. Measures of pubertal development, self-reported stress, parent reports of child depressive symptoms and fearful temperament, and cardiac measures of sympathetic and parasympathetic activity were also obtained. Significant increases in the home cortisol baselines were found with age and pubertal development. Cortisol stress reactivity differed by age group with 11-year-olds and 13-year-old boys showing blunted reactivity and 9-year-olds, 13-year-old girls, and 15-year-olds showing significant cortisol reactions. Cortisol reactivity correlated marginally with sexual maturation. Measures of sympathetic activity revealed increased sympathetic modulation with age. Higher sympathetic tone was associated with more fearful temperament, whereas greater cortisol reactivity was associated with more anxious and depressed symptoms for girls. The importance of these findings for the hypothesis that puberty-associated increases in hypothalamic-pituitary-adrenal axis activity heightens the risk of psychopathology is discussed.

The onset of puberty: effects on the psychophysiology of defensive and appetitive motivation

We examined puberty-specific effects on affect-related behavior and on the psychophysiology of defensive and appetitive motivation while controlling for age. Adolescents (N = 94, ages = 12 and 13 years) viewed 75 pictures (International Affective Picture System: pleasant, neutral, and aversive) while listening to auditory probes. Startle response and postauricular (PA) reflex were collected as measures of defensive and appetitive motivation, respectively. Pubertal status and measures of anxiety/stress reaction and sensation/thrill seeking were obtained. Mid-/late pubertal adolescents showed enhanced startle amplitude across all picture valences. A Puberty x Valence interaction revealed that mid-/late pubertal adolescents showed appetitive potentiation of the PA, whereas pre-/early pubertal adolescents showed no modulation of the PA reflex. Mid-/late pubertal adolescents also scored significantly higher on measures of sensation/thrill seeking than did their pre-/early pubertal peers and puberty moderated the association between psychophysiology and behavioral measures, suggesting that it plays a role in reorganizing defensive and appetitive motivational systems.

Pubertal changes in emotional information processing: pupillary, behavioral, and subjective evidence during emotional word identification

This study investigated pupillary and behavioral responses to an emotional word valence identification paradigm among 32 pre-/early pubertal and 34 mid-/late pubertal typically developing children and adolescents. Participants were asked to identify the valence of positive, negative, and neutral words while pupil dilation was assessed using an eyetracker. Mid-/late pubertal children showed greater peak pupillary reactivity to words presented during the emotional word identification task than pre-/early pubertal children, regardless of word valence. Mid-/late pubertal children also showed smaller sustained pupil dilation than pre-/early pubertal children after the word was no longer on screen. These findings were replicated controlling for participants' age. In addition, mid-/late pubertal children had faster reaction times to all words, and rated themselves as more emotional during their laboratory visit compared to pre-/early pubertal children. Greater recall of emotional words following the task was associated with mid-/late pubertal status, and greater recall of emotional words was also associated with higher peak pupil dilation. These results provide physiological, behavioral, and subjective evidence consistent with a model of puberty-specific changes in neurobehavioral systems underpinning emotional reactivity.

Video-based road commentary training improves hazard perception of young drivers in a dual task

This study used a video-based hazard perception dual task to compare the hazard perception skills of young drivers with middle aged, more experienced drivers and to determine if these skills can be improved with video-based road commentary training. The primary task required the participants to detect and verbally identify immediate hazard on video-based traffic scenarios while concurrently performing a secondary tracking task, simulating the steering of real driving. The results showed that the young drivers perceived fewer immediate hazards (mean=75.2%, n=24, 19 females) than the more experienced drivers (mean=87.5%, n=8, all females), and had longer hazard perception times, but performed better in the secondary tracking task. After the road commentary training, the mean percentage of hazards detected and identified by the young drivers improved to the level of the experienced drivers and was significantly higher than that of an age and driving experience matched control group. The results will be discussed in the context of psychological theories of hazard perception and in relation to road commentary as an evidence-based training intervention that seems to improve many aspects of unsafe driving behaviour in young drivers.

Effects of stress throughout the lifespan on the brain, behaviour and cognition

Chronic exposure to stress hormones, whether it occurs during the prenatal period, infancy, childhood, adolescence, adulthood or aging, has an impact on brain structures involved in cognition and mental health. However, the specific effects on the brain, behaviour and cognition emerge as a function of the timing and the duration of the exposure, and some also depend on the interaction between gene effects and previous exposure to environmental adversity. Advances in animal and human studies have made it possible to synthesize these findings, and in this Review a model is developed to explain why different disorders emerge in individuals exposed to stress at different times in their lives.

Street racing: a neglected research area?

OBJECTIVE

To review: (1) the extent and frequency of street racing and its consequences; (2) the characteristics of street racers; (3) explanatory theories for street racing; (4) the legal issues; and (5) the best methods of preventing street racing.

METHODS

Review of academic and other literature.

RESULTS

Very limited official statistics are available on street racing offenses and related collisions, in part because of the different jurisdictional operational definitions of street racing and the ability of police to determine whether street racing was a contributing factor. Some data on prevalence of street racing have been captured through social surveys and they found that between 18.8 and 69.0 percent of young male drivers from various international jurisdictions have reported street racing. Moreover, street racing is found to be associated with other risky behaviors, substance abuse, and delinquent activities. The limited evidence available on street racing suggests that it has increased in the last decade.

CONCLUSIONS

Street racing is a neglected research area and the time has come to examine the prevalence and causes of street racing and the effectiveness of various street racing countermeasures.

Social environments and physical aggression among 21,107 students in the United States and Canada

BACKGROUND

Physical aggression is an important issue in North American populations. The importance of students' social environments in the occurrence of physical aggression requires focused study. In this study, reports of physical aggression were examined in relation to social environment factors among national samples of students from Canada and the United States.

METHODS

Students in grades 6-10 from the United States (n = 14,049) and Canada (n = 7058) who had participated in the Health Behaviour in School-aged Children Survey (HBSC) were studied. Rates of students' physical aggression were compared between the 2 countries. School, family, socioeconomic, and peer-related factors were considered as potential risk factors. A simple social environment risk score was developed using the US data and was subsequently tested in the Canadian sample.

RESULTS

Risks for physical aggression were consistently higher among United States versus Canadian students, but the magnitude of these differences was modest. The relative odds of physical aggression increased with reported environmental risk. To illustrate, US boys in grades 6-8 reporting the highest social environment risk score (5+) experienced a relative odds of physical aggression 4.02 (95% CI 2.7-5.9) times higher than those reporting the lowest score (adjusted OR for risk scores 0 through 5+ was 1.00, 1.19, 2.10, 2.01, 3.71, and 4.02, respectively, p(trend) < .001).

CONCLUSIONS

Unexpectedly, rates of physical aggression and associations between social environments and students' aggression were remarkably similar in Canada and the United States. Family, peer, and school social environments serve as risk or protective factors, with significant cumulative impact on physical aggression in both countries. Given the observed high rates and the many negative effects of aggression on long-term health, school policies aimed at the reduction of such behavior remain a clear priority.

Psychosocial functioning among bipolar youth

BACKGROUND

Evidence indicates that children and adolescents with bipolar disorder (BP) experience significant functional impairment. However, little is known about the association between psychosocial functioning and episodes of illness, demographic, and clinical variables in this population.

METHODS

Subjects included 446 patients aged 7 to 17 diagnosed with DSM-IV bipolar disorder via the K-SADS for the Course and Outcome of Bipolar Youth (COBY) study. The Psychosocial Functioning Schedule of the Adolescent Longitudinal Interval Follow-Up Assessment (A-LIFE) was administered at study intake.

RESULTS

Mild to moderate levels of psychosocial impairment were evident in work (includes academics), interpersonal, and overall domains of functioning among BP youth. Multivariate analyses indicated that the strongest predictors of psychosocial impairment were adolescence (regardless of age of onset), current mood episode, current affective symptom severity, current psychotic symptoms, and current comorbid conduct disorder. Bipolar youth in-episode were significantly more impaired than those in partial remission/recovery in every functional domain examined and were less satisfied with their functioning. Yet, BP youth in partial remission/recovery reported significant psychosocial impairment.

LIMITATIONS

Limitations include the reliance on patient and parent retrospective report of psychosocial functioning. Additionally, we did not account for the impact of psychosocial and pharmacological interventions on functioning.

CONCLUSIONS

Findings suggest pediatric BP is associated with significant impairment in psychosocial functioning during and between episodes, with greater impairment during mood episodes than during partial remission/recovery. Additionally, functional impairment in BP appears to increase during adolescence regardless of age of onset. Clinicians should carefully assess and address psychosocial impairment during and between mood episodes, with particular attention to the functioning of BP adolescents.

Mad, sad and hormonal: the gendered nature of adolescent sleep disturbance

Up to 40 percent of adolescents experience some form of sleep difficulty, with adolescent girls often reporting higher levels of sleep disturbance and daytime fatigue than boys. This article explores the literature surrounding female adolescent sleep disturbance. The findings reveal that sleep problems in young women can be linked to girls being at an increased risk for puberty-related fatigue, sexual abuse, a higher prevalence of mental illness and sensitivity to familial disruption, and increased domestic and grooming expectations. Implications for nursing practice include initiating conversations about sleep, sleep disturbance and sleeping arrangements when working with adolescent girls. Nurses should gather accurate sleep histories, provide adolescent girls and their caregivers with information and recommend interventions to improve sleep if necessary. Nurses should remain sensitive to the confounding effects of pubertal status, menarche and the cyclic release of hormones when designing and conducting future research into female adolescent sleep disturbance.

Neurobiology of empathy and callousness: implications for the development of antisocial behavior

Information on the neurobiology of empathy and callousness provides clinicians with an opportunity to develop sophisticated understanding of mechanisms underpinning antisocial behavior and its counterpart, moral decision-making. This article provides an integrated in-depth review of hormones (e.g. peripheral steroid hormones such as cortisol) and brain structures (e.g. insula, anterior cingulate cortex, and amygdala) implicated in empathy, callousness, and psychopathic-like behavior. The overarching goal of this article is to relate these hormones and brain structures to moral decision-making. This review will begin in the brain, but will then integrate information about biological functioning in the body, specifically stress-reactivity. Our aim is to integrate understanding of neural processes with hormones such as cortisol, both of which have demonstrated relationships to empathy, psychopathy, and antisocial behavior. The review proposes that neurobiological impairments in individuals who display little empathy are not necessarily due to a reduced ability to understand the emotions of others. Instead, evidence suggests that individuals who show little arousal to the distress of others likewise show decreased physiological arousal to their own distress; one manifestation of reduced stress reactivity may be a dysfunction in empathy, which supports psychopathic-like constructs (e.g. callousness). This integration will assist in the development of objective methodologies that can inform and monitor treatment interventions focused on decreasing antisocial behavior.

Behavioral genetic analyses of prosocial behavior in adolescents

Prosocial behavior is an important aspect of normal social and psychological development. Adult and child twin studies typically estimate the heritability of prosocial behavior to be between 30 and 50%, although relatively little is known about genetic and environmental influences upon prosocial behavior in adolescence. We therefore examined reports of prosocial behavior in a large longitudinal family study of 1160 adolescent twin pairs (aged between 13 and 19 years). Prosocial behavior was assessed at two time points by self-report and at the second time point by additional parent-ratings using the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997). Adolescent females were reported to be significantly more prosocial than males (p < .001). Univariate analyses primarily showed moderate heritability and large nonshared environmental influences. There was a moderate genetic correlation between self- and parent-reported prosocial behaviour, suggesting that both types of rater were tapping into genetically overlapping constructs. Longitudinal analyses revealed that continuity was largely explained by genes. Unique environmental influences were predominantly time-specific and were the major source of individual differences.

A critical review of the empirical literature on the relation between anxiety and puberty

The current paper critically reviews the empirical literature focused on the association between puberty and anxiety. A detailed review of more than 45 empirical articles is provided. There is some evidence that among girls, but not boys, a more advanced pubertal status (controlling for age) is associated with higher reported anxiety symptoms. Also among girls, earlier pubertal timing is linked to higher anxiety scores. It is unclear whether early puberty may lead to increased anxiety or if high anxiety influences pubertal timing. With respect to hormones, there were relatively few significant associations for girls, although this literature is very small. Among boys, several studies reported positive associations between both gonadal and adrenal hormones and anxiety. The direction of effect for these finding is also unstudied. The primary limitation of the hormone-anxiety literature pertains to the absence of pubertal measures in samples of youth in which hormones are measured. The paper concludes with a comprehensive examination of the methodological strengths and weaknesses of the literature and recommendations for future work.

Positive and negative emotionality: trajectories across six years and relations with social competence

The goals of the present study were to examine (1) the mean-level stability and differential stability of children's positive emotional intensity, negative emotional intensity, expressivity, and social competence from early elementary school-aged to early adolescence, and (2) the associations between the trajectories of children's emotionality and social functioning. Using four waves of longitudinal data (with assessments 2 years apart), parents and teachers of children (199 kindergarten through third grade children at the first assessment) rated children's emotion-related responding and social competence. For all constructs, there was evidence of mean-level decline with age and stability in individual differences in rank ordering. Based on age-centered growth-to-growth curve analyses, the results indicated that children who had a higher initial status on positive emotional intensity, negative emotional intensity, and expressivity had a steeper decline in their social skills across time. These findings provide insight into the stability and association of emotion-related constructs to social competence across the elementary and middle school years.

Heightened stress responsiveness and emotional reactivity during pubertal maturation: Implications for psychopathology

The onset of adolescence, and more specifically the advent of pubertal maturation, represents a key developmental window for understanding the emergence of psychopathology in youth. The papers in this special section examine normative differences in the neurobiology of stress and emotional functioning over the peripubertal period. The work in this special section helps to fill in gaps in our understanding of key mechanisms that may contribute to increased vulnerabilities in behavioral and psychiatric morbidity during this developmental period.

Heightened stress responsivity and emotional reactivity during pubertal maturation: Implications for psychopathology

This commentary reviews and reflects on the studies of this special section: studies that collectively provide compelling evidence for meaningful changes in stress- and emotionally reactive psychophysiological systems with the transition from middle childhood into adolescence. The observed changes were complex and often overlaid upon ontogenetic differences in basal levels of activation of these systems. Maturational increases in responsiveness to stressors were stressor dependent and differentially expressed across autonomic and hormonal measures. Pubertal status increased the impact of some affective valence manipulations, although not significantly influencing others, including negative affect-related potentiation of startle/reflexes. Such ontogenetic increases in stressor and affect sensitivity may have implications for developmental psychopathology. Developmental increases in stressor reactivity may normally aid youth in responding adaptively to the challenges of adolescence, but may result in stress dysregulation among at-risk adolescents, increasing further their vulnerability for psychopathology. Pubertal-related increases in sensitivity to emotionally laden stimuli may exacerbate individual predispositions for exaggerated affective processing, perhaps contributing to the emergence of psychological disorders in these youth. Together, these studies, with their innovative use of autonomic, reflexive, and hormonal measures to index age- and pubertal-related changes in reactivity to stressors and affective stimuli, provide promising directions for future research. Some of these, along with a few cautionary notes, are outlined.

Impulsivity and its Relationship to Risky Sexual Behaviors and Drug Abuse

We examined a mediational model of the inter-relationship of drug use, sexual risk and impulsivity in a sample of young adults (N = 89), of which almost half displayed highly disruptive behaviors as children. We chose a mediational model given the emerging evidence that impulsivity is an underlying risk factor for many youth health risk problems, including sexual risk behaviors. The findings supported a partial mediational model in that the three target variables were significantly related to each other, yet the association of drug use and sexual risk was significantly reduced (although not to zero) when controlled by impulsivity. The findings support the view that the association of drug use and sexual risk behaviors is partially mediated by impulsivity, as well as the broader theory that youth with deficits in self-regulatory behavioral systems confer a greater likelihood of engaging in risky behaviors. Study implications and limitations are discussed.

Decreased postnatal neurogenesis in the hippocampus combined with stress experience during adolescence is accompanied by an enhanced incidence of behavioral pathologies in adult mice

BACKGROUND

Adolescence is a vulnerable period in that stress experienced during this time can affect the incidence of psychiatric disorders later, during adulthood. Neurogenesis is known to be involved in the postnatal development of the brain, but its role in determining an individual's biological vulnerability to the onset of psychiatric disorders has not been addressed.

RESULTS

We examined the role of postnatal neurogenesis during adolescence, a period between 3 to 8 weeks of age in rodents. Mice were X-irradiated at 4 weeks of age, to inhibit postnatal neurogenesis in the sub-granule cell layer of the hippocampus. Electrical footshock stress (FSS) was administered at 8 weeks old, the time at which neurons being recruited to granule cell layer were those that had begun their differentiation at 4 weeks of age, during X-irradiation. X-irradiated mice subjected to FSS during adolescence exhibited decreased locomotor activity in the novel open field, and showed prepulse inhibition deficits in adulthood. X-irradiation or FSS alone exerted no effects on these behaviors.

CONCLUSION

These results suggest that mice with decreased postnatal neurogenesis during adolescence exhibit vulnerability to stress, and that persistence of this condition may result in decreased activity, and cognitive deficits in adulthood.

Individual differences and developmental change in the ERN response: implications for models of ACC function

The anterior cingulate cortex (ACC) has been associated with conditions precipitating an increase in effortful processing or increased attention, including the presence of conflicting information and the detection of errors. The error-related negativity (ERN), an electrocortical response, has been used as a marker for these conditions. The ERN amplitude however is subject to developmental change across the lifespan as well as being sensitive to individual differences in personality, affect, and autonomic responsivity. In this review, we examine the implications of such influences for a standard ACC model of conflict processing, and outline the need of any model of ACC function to include mechanisms that allow for the integration of neurovisceral and cognitive domains.

Post-training ethanol disrupts trace conditioned fear in rats: effects of timing of ethanol, dose and trace interval duration

Ethanol has complex effects on memory performance, although hippocampus-dependent memory may be especially vulnerable to disruption by acute ethanol intoxication occurring during or shortly after a training episode. In the present experiments, the effects of post-training ethanol on delay and trace fear conditioning were examined in adolescent rats. In Experiment 1, 30-day-old Sprague-Dawley rats were given delay or trace conditioning trials in which a 10s flashing light CS was paired with a 0.5 mA shock US. For trace groups, the trace interval was 10 s. On days 31-33, animals were administered ethanol once daily (0.0 or 2.5 g/kg via intragastric intubation), and on day 34 animals were tested for CS-elicited freezing. Results showed that post-training ethanol affected the expression of trace, but had no effect on delay conditioned fear. Experiment 2 revealed that this effect was dose-dependent; doses lower than 2.5 g/kg were without effect. Experiment 3 evaluated whether proximity of ethanol to the time of training or testing was critical. Results show that ethanol administration beginning 24h after training was more detrimental to trace conditioned freezing than administration that was delayed by 48 h. Finally, in Experiment 4 animals were trained with one of three different trace intervals: 1, 3 or 10s. Results indicate that post-training administration of 2.5 g/kg ethanol disrupted trace conditioned fear in subjects trained with a 10s, but not with a 1 or 3s, trace interval. Collectively the results suggest that ethanol administration impairs post-acquisition memory processing of hippocampus-dependent trace fear conditioning.

Adolescent Suicidal Behavior and Substance Use: Developmental Mechanisms

Adolescent suicidal behaviors and substance use are disturbingly common. Research suggests overlap of some of the etiological mechanisms for both adolescent suicidal behavior and substance use, yet clear understanding of the complex relations between these behaviors and their causal underpinnings is lacking. A growing body of evidence and a diathesis model (Mann et al. 1999; Mann, 2003) highlight the importance of impulse control as a proximal risk factor for adolescent suicidal and substance use behaviors. This literature review extends current theory on the relationships between adolescent suicidal behavior and substance use by: (1) examining how, when, and to what extent adolescent development is affected by poor impulse control, stressful life events, substance use behavior, and biological factors; (2) presenting proposed causal mechanisms by which these risk factors interact to increase risk for suicidal behaviors and substance use; and (3) proposing specific new hypotheses to extend the diathesis model to adolescents at risk for suicide and substance use. More specifically, new hypotheses are presented that predict bidirectional relationships between stressful life events and genetic markers of 5-HT dysregulation; substance use behavior and impulsivity; and substance use behavior and suicide attempts. The importance of distinguishing between different developmental trajectories of suicidal and substance use behaviors, and the effects of specific risk and protective mechanisms are discussed. Use of new statistical approaches that provide for the comparison of latent growth curves and latent class models is recommended to identify differences in developmental trajectories of suicidal behavior and substance use. Knowledge gained from these prospective longitudinal methods should lead to greater understanding on the timing, duration, and extent to which specific risk and protective factors influence the outcomes of suicidal behavior and substance use. In turn, findings from these studies should inform researchers who conduct future treatment and prevention studies.

A neural model of voluntary and automatic emotion regulation: implications for understanding the pathophysiology and neurodevelopment of bipolar disorder

The ability to regulate emotions is an important part of adaptive functioning in society. Advances in cognitive and affective neuroscience and biological psychiatry have facilitated examination of neural systems that may be important for emotion regulation. In this critical review we first develop a neural model of emotion regulation that includes neural systems implicated in different voluntary and automatic emotion regulatory subprocesses. We then use this model as a theoretical framework to examine functional neural abnormalities in these neural systems that may predispose to the development of a major psychiatric disorder characterized by severe emotion dysregulation, bipolar disorder.

A meta-analysis of marijuana and alcohol use by socio-economic status in adolescents aged 10-15 years

OBJECTIVES

A majority of population-based studies suggest prevalence of drug and alcohol risk behaviour increases during late adolescence to early adulthood. The purpose of this systematic literature review is to clarify if socio-economic status (SES) is a determinant of marijuana and alcohol risk behaviour in adolescents between the ages of 10-15 years.

METHODS

We performed a meta-analysis to identify published or unpublished papers between January 1, 1980 and February 9, 2007 that reviewed marijuana and alcohol risk behaviour by SES in adolescents aged 10-15 years.

SYNTHESIS

We found nine studies that fulfilled our inclusion criteria and passed the methodological quality review. The prevalence of marijuana and alcohol risk behaviour was 22% higher (RR = 1.22; 95% CI 1.14-1.31) in adolescents with low SES in comparison to adolescents with higher SES. Stratification by country of origin revealed that American and New Zealand studies had statistically significant variability in the reported effects as compared to European and UK studies.

DISCUSSION

The evidence suggests that low SES has an inverse association with the prevalence of marijuana and alcohol risk behaviour in adolescents between the ages of 10-15 years. Higher rates of marijuana and alcohol risk behaviour among lower SES adolescents may impact emotional development, limit future educational and occupational achievement, and increase the likelihood for adult marijuana and alcohol addiction.

CONCLUSION

Lower SES adolescents have higher rates of marijuana and alcohol risk behaviour than higher SES adolescents.

Development of anterior cingulate functional connectivity from late childhood to early adulthood

Human cerebral development is remarkably protracted. Although microstructural processes of neuronal maturation remain accessible only to morphometric post-mortem studies, neuroimaging tools permit the examination of macrostructural aspects of brain development. The analysis of resting-state functional connectivity (FC) offers novel possibilities for the investigation of cerebral development. Using seed-based FC methods, we examined the development of 5 functionally distinct cingulate-based intrinsic connectivity networks (ICNs) in children (n = 14, 10.6 +/- 1.5 years), adolescents (n = 12, 15.4 +/- 1.2) and young adults (n=14, 22.4 +/- 1.2). Children demonstrated a more diffuse pattern of correlation with voxels proximal to the seed region of interest (ROI) ("local FC"), whereas adults exhibited more focal patterns of FC, as well as a greater number of significantly correlated voxels at long distances from the seed ROI. Adolescents exhibited intermediate patterns of FC. Consistent with evidence for different maturational time courses, ICNs associated with social and emotional functions exhibited the greatest developmental effects. Our findings demonstrate the utility of FC for the study of developing functional organization. Moreover, given that ICNs are thought to have an anatomical basis in neuronal connectivity, measures of FC may provide a quantitative index of brain maturation in healthy subjects and those with neurodevelopmental disorders.

Reciprocal associations between boys' externalizing problems and mothers' depressive symptoms

Although much has been written about the utility of applying transactional models to the study of parenting practices, relatively few researchers have used such an approach to examine how children influence maternal well-being throughout their development. Using a sample of males from predominantly low-income families, the current study explored reciprocal relations between boys' overt disruptive behavior (boys' ages 5 to 10 years) and maternal depressive symptoms. We then examined this model with youth-reported antisocial behaviors (ASB) and maternal depressive symptoms when the boys were older, ages 10 to 15. In middle childhood, evidence was found for both maternal and child effects from boys' ages 5 to 6 using both maternal and alternative caregiver report of child aggressive behavior. In the early adolescence model, consistent maternal effects were found, and child effects were evident during the transition to adolescence (boys' ages 11 to 12). The findings are discussed in reference to reciprocal models of child development and prevention efforts to reduce both maternal depression and the prevalence of child antisocial behavior.

Completed suicide in childhood

Suicide in children and young adolescents up to 14 years of age has increased in many countries, warranting research and clinical awareness. International reported suicide rates per 100,000 in this young population vary between 3.1 and 0 (mean rate worldwide, approximately 0.6/100.000; male-female ratio, 2:1). Suicide occurs only in vulnerable children; this vulnerability begins with parental mood disorder and impulsive aggression, and family history of suicide. Childhood affective and disruptive disorders and abuse are the most often reported psychiatric risk factors. Suicide becomes increasingly common after puberty, most probably because of pubertal onset of depression and substance abuse, which substantially aggravate suicide risk. Biologic findings are scarce; however, serotonergic dysfunction is assumed. The most common precipitants are school and family problems and may include actual/anticipated transitions in these environments. Suicides in children and young adolescents up to 14 years of age often follow a brief period of stress. Cognitive immaturity/misjudgment, age-related impulsivity, and availability of suicide methods play an important role. Psychologic autopsy studies that focus on suicides in this age group are needed.

Biological substrates of emotional reactivity and regulation in adolescence during an emotional go-nogo task

BACKGROUND

Adolescence is a transition period from childhood to adulthood that is often characterized by emotional instability. This period is also a time of increased incidence of anxiety and depression, underscoring the importance of understanding biological substrates of behavioral and emotion regulation during adolescence. Developmental changes in the brain in concert with individual predispositions for anxiety might underlie the increased risk for poor outcomes reported during adolescence. We tested the hypothesis that difficulties in regulating behavior in emotional contexts in adolescents might be due to competition between heightened activity in subcortical emotional processing systems and immature top-down prefrontal systems. Individual differences in emotional reactivity might put some teens at greater risk during this sensitive transition in development.

METHODS

We examined the association between emotion regulation and frontoamygdala circuitry in 60 children, adolescents, and adults with an emotional go-nogo paradigm. We went beyond examining the magnitude of neural activity and focused on neural adaptation within this circuitry across time with functional magnetic resonance imaging.

RESULTS

Adolescents showed exaggerated amygdala activity relative to children and adults. This age-related difference decreased with repeated exposures to the stimuli, and individual differences in self-ratings of anxiety predicted the extent of adaptation or habituation in amygdala. Individuals with higher trait anxiety showed less habituation over repeated exposures. This failure to habituate was associated with less functional connectivity between ventral prefrontal cortex and amygdala.

CONCLUSIONS

These findings suggest that exaggerated emotional reactivity during adolescence might increase the need for top-down control and put individuals with less control at greater risk for poor outcomes.

Acute disinhibiting effects of alcohol as a factor in risky driving behavior

Automobile crash reports show that up to 40% of fatal crashes in the United States involve alcohol and that younger drivers are over-represented. Alcohol use among young drivers is associated with impulsive and risky driving behaviors, such as speeding, which could contribute to their over-representation in alcohol-related crash statistics. Recent laboratory studies show that alcohol increases impulsive behaviors by impairing the drinker's ability to inhibit inappropriate actions and that this effect can be exacerbated in conflict situations where the expression and inhibition of behavior are equally motivating. The present study tested the hypothesis that this response conflict might also intensify the disruptive effects of alcohol on driving performance. Fourteen subjects performed a simulated driving and a cued go/no-go task that measured their inhibitory control. Conflict was motivated in these tasks by providing equal monetary incentives for slow, careful behavior (e.g., slow driving, inhibiting impulses) and for quick, abrupt behavior (fast driving, disinhibition). Subjects were tested under two alcohol doses (0.65 g/kg and a placebo) that were administered twice: when conflict was present and when conflict was absent. Alcohol interacted with conflict to impair inhibitory control and to increase risky and impaired driving behavior on the drive task. Also, individuals whose inhibitory control was most impaired by alcohol displayed the poorest driving performance under the drug. The study demonstrates potentially serious disruptions to driving performance as a function of alcohol intoxication and response conflict, and points to inhibitory control as an important underlying mechanism.

Differences in endocrine parameters and psychopathology in girls with premature adrenarche versus on-time adrenarche

Girls with premature adrenarche (PA) are at risk for multiple problems related to exaggerated androgen synthesis. Whether PA carries a risk of psychopathology remains unknown. This study examined group differences in: (a) anthropometric and endocrine parameters, and (b) mood and behavior problems, in 6-8 year-old girls with PA (n = 40) compared to on-time adrenarche girls (n = 36). PA girls were taller (p < or =0.05) and heavier (p < or =0.01) than the on-time adrenarche girls but body mass index showed no difference. PA girls had significantly (p <0.05) higher adrenal androgen and testosterone concentrations but not cortisol or leptin. PA girls also had significantly more oppositional defiant disorder, and higher symptom counts reflecting anxiety, mood or disruptive behavior disorders. PA girls may be more vulnerable to psychopathology than on-time adrenarche girls. The challenge of future studies is to determine which PA girls are at risk for psychopathology and which are more resilient.

Prevention of alcohol problems in Dutch youth: missed opportunities and new developments

Binge drinking among young people is a problem in the Netherlands. This article outlines the current Dutch approach to alcohol prevention in this target group. It is argued that well-enforced evidence-based control measures are lacking despite renewed political interest in them. Politicians often favor alcohol education, but to increase the effectiveness of alcohol prevention, a combined approach of policy measures, enforcement, and education is needed. Translation of education and policy-based measures is discussed.

Underage drinking: a developmental framework

A developmental framework for understanding and addressing the problem of underage alcohol consumption is presented. The first section presents the rationale for a developmental approach, including striking age-related data on patterns of onset, prevalence, and course of alcohol use and disorders in young people. The second section examines the fundamental meaning of a developmental approach to conceptualizing underage drinking. The third section delineates contemporary principles of developmental psychopathology as a guide to future research and intervention efforts. Strategic, sensitive, and effective efforts to address the problem of underage drinking will require a developmentally informed approach to research, prevention, and treatment.

Promoting Intrapersonal Qualities in Adolescents

Given the number of negative influences on youth and the resultant potential for adverse outcomes, it is crucial to support their positive development. Leadership training programs can promote the development of adaptive intrapersonal qualities. The Teen Leadership Breakthrough (TLB) program claims to create sustainable changes in youth using experiential activities, direct instruction, and feedback to teach leadership skills. This study evaluated the TLB program's efficacy in developing intrapersonal skills in 10th- and 11th-grade students. Participants were randomly assigned to a control or treatment group. Assessment of emotional intelligence and self-concept occurred prior to, immediately after, 6 weeks and 6 months following the intervention. Results indicated that the TLB program created sustainable changes emotional intelligence and self-concept. Although these results are encouraging, further research is needed to investigate the effectiveness of the TLB program in broader demographic groups and to examine different outcomes.

A Social Neuroscience Perspective on Adolescent Risk-Taking

This article proposes a framework for theory and research on risk-taking that is informed by developmental neuroscience. Two fundamental questions motivate this review. First, why does risk-taking increase between childhood and adolescence? Second, why does risk-taking decline between adolescence and adulthood? Risk-taking increases between childhood and adolescence as a result of changes around the time of puberty in the brain's socio-emotional system leading to increased reward-seeking, especially in the presence of peers, fueled mainly by a dramatic remodeling of the brain's dopaminergic system. Risk-taking declines between adolescence and adulthood because of changes in the brain's cognitive control system - changes which improve individuals' capacity for self-regulation. These changes occur across adolescence and young adulthood and are seen in structural and functional changes within the prefrontal cortex and its connections to other brain regions. The differing timetables of these changes make mid-adolescence a time of heightened vulnerability to risky and reckless behavior.

Maternal predictors of rejecting parenting and early adolescent antisocial behavior

The present study examined relations among maternal psychological resources, rejecting parenting, and early adolescent antisocial behavior in a sample of 231 low-income mothers and their sons with longitudinal assessments from age 18 months to 12 years. The maternal resources examined were age at first birth, aggressive personality, and empathy. Each of the maternal resources predicted rejecting parenting during early childhood in structural equation models that controlled for toddler difficult temperament, and rejecting parenting in early childhood predicted antisocial behavior in early adolescence. Rejecting parenting accounted for the indirect effect of each of the maternal resources on antisocial behavior, but a direct effect was also supported between maternal aggressive personality and youth antisocial behavior. Results highlight the importance of these relatively understudied maternal resources and have implications for prevention and intervention programs that focus on parenting during early childhood.

Psychosocial functioning of adults who experienced substance use disorders as adolescents

The authors examined whether substance use disorder (SUD) before age 19 was associated with functioning at age 30. Participants (N = 773) were assessed twice during adolescence and at ages 24 and 30. Eight of 14 adult measures were associated with adolescent SUD: education, unemployment, income, risky sexual behavior, suicide attempt, coping, stressful life events, and global adjustment. After adolescent comorbidity and functioning and adult SUD were controlled for, education and unemployment remained associated, and three variables emerged as significant: being a parent (significant only for participants without adult SUD), being currently married, and having decreased life satisfaction (significant only for participants with adult SUD). Adolescent SUD is associated with numerous functioning difficulties at age 30, some of which appear to be related to recurrent SUD, comorbid adolescent disorders, or functioning problems already evident in adolescence.

A model-based cluster analysis approach to adolescent problem behaviors and young adult outcomes

Data from a community-based sample of 1,126 10th- and 11th-grade adolescents were analyzed using a model-based cluster analysis approach to empirically identify heterogeneous adolescent subpopulations from the person-oriented and pattern-oriented perspectives. The model-based cluster analysis is a new clustering procedure to investigate population heterogeneity utilizing finite mixture multivariate normal densities and accordingly to classify subpopulations using more rigorous statistical procedures for the comparison of alternative models. Four cluster groups were identified and labeled multiproblem high-risk, smoking high-risk, normative, and low-risk groups. The multiproblem high risk exhibited a constellation of high levels of problem behaviors, including delinquent and sexual behaviors, multiple illicit substance use, and depressive symptoms at age 16. They had risky temperamental attributes and lower academic functioning and educational expectations at age 15.5 and, subsequently, at age 24 completed fewer years of education, and reported lower levels of physical health and higher levels of continued involvement in substance use and abuse. The smoking high-risk group was also found to be at risk for poorer functioning in young adulthood, compared to the low-risk group. The normative and the low risk groups were, by and large, similar in their adolescent and young adult functioning. The continuity and comorbidity path from middle adolescence to young adulthood may be aided and abetted by chronic as well as episodic substance use by adolescents.

Development of action monitoring through adolescence into adulthood: ERP and source localization

In this study we examined the development of three action monitoring event-related potentials (ERPs) - the error-related negativity (ERN/Ne), error positivity (P(E)) and the N2 - and estimated their neural sources. These ERPs were recorded during a flanker task in the following groups: early adolescents (mean age = 12 years), late adolescents (mean age = 16 years), and adults (mean age = 29 years). The amplitudes of the ERN/Ne and N2 were greater in the adult and late adolescent groups than in the early adolescent group. Both of these components had neural sources in the anterior cingulate cortex (ACC). Although P(E) was present across groups, P(E) amplitude was greater in the late adolescent group compared to the adult group and also had neural sources in the ACC. ERN/Ne amplitude was related to post-error slowing across age groups; it was related to task performance only in the adult group. These findings are discussed in light of the role of the maturation of the ACC in the development of action monitoring processes.

Iron deficiency and child development

Iron deficiency is widespread in infants and young children, especially in developing countries. Animal models provide convincing evidence that, despite iron repletion, iron deficiency during the brain growth spurt alters metabolism and neurotransmission, myelination, and gene and protein profiles. In the human, there is compelling evidence that 6- to 24-month-old infants with iron-deficiency anemia are at risk for poorer cognitive, motor, social-emotional, and neurophysiologic development in the short- and long-term outcome. In contrast to inconsistent developmental effects of iron therapy for iron-deficient infants, recent large, randomized trials of iron supplementation in developing countries uniformly show benefits of iron, especially on motor development and social-emotional behavior. These results indicate that adverse effects can be prevented and/or reversed with iron earlier in development or before iron deficiency becomes severe or chronic. New findings also point to the need for more attention to the developmental effects of prenatal iron deficiency.

Comparison of infant and adult rats in exploratory activity, diurnal patterns, and responses to novel and anxiety-provoking environments

Infant rats emerge from the maternal nest at Postnatal Day 17-18 to have their first critical environmental experiences; they may be particularly sensitive to experiences or experimental interventions that can affect their adult capacity. The authors address open questions on 2 components of normative environmental exploration, locomotor activity and response to anxiety-provoking locations, in Postnatal Day 18 infant and Postnatal Day 60 adult rats. The authors compare diurnal patterns of locomotor activity, wheel running, novel and familiar open-field activity, and 2 measures of anxiety. Infants have an equivalent capacity to adults for locomotor activity and wheel running and a fundamentally adult-like diurnal rhythm, except that they do not anticipate light-dark transitions, are more perturbable at their most somnolent, and are more or less active during specific limited phases than adults. Infants initially have a lower rate of locomotor activity in novel environments and have a greater willingness to be active in anxiety-provoking locations. Such differences may allow enhanced gathering of environmental information by the infant and are important to consider in the design of experiments using infants.

Promoting adolescent health

The aim is to discuss why paediatricians should be involved in adolescent health care and provide youth-friendly-health-services. Global epidemiological data on morbidity and mortality demonstrate that much of ill health in the short and long run are connected to adolescent behaviour and in theory available for prevention. Young people seemingly lose their heads and do not consider dangers. Recent research on brain development provides us with an understanding how this may have a biological base. Also psychology has long taught us how adolescents use experimental behaviours as means to satisfy developmental needs and explore identity. Prevention and health promotion are areas of research where much more needs to be done. There is also a lack of venues for publishing even excellent studies in this field.

Neurocognitive correlates of problem behavior in environmentally at-risk adolescents

OBJECTIVE

This study prospectively examines the correlation between neurocognitive (NC) functioning and problem behavior in early adolescence.

METHODS

As part of a longitudinal study, African American urban youths of lower socioeconomic status, mean age 12.1 years (SD=1.2, n=111), were administered a battery of 16 NC tasks assessing eight NC systems (two tasks per system) including four systems primarily associated with frontal cortex and four primarily associated with nonfrontal cortex. The former systems included (1) executive cognitive functioning (ECF), (2) cognitive control, (3) working memory, and (4) reward processing. The latter systems included (5) receptive language, (6) spatial cognition, (7) visual cognition, and (8) memory. The Teacher's Report Form of the Achenbach System of Empirically Based Assessment was performed approximately at the same age that the NC assessments were performed. Bivariate correlations were calculated between the eight NC system composite scores and the externalizing scores.

RESULTS

Significant negative relationships were found between ECF and receptive language ability and externalizing behavior. Further analyses, using linear regression, showed that receptive language was more predictive of externalizing behavior than ECF.

CONCLUSION

Based on these results we conclude that (1) NC functioning, specifically in ECF and in receptive language systems, was associated with adolescent problem behavior and (2) receptive language was more strongly associated with problem behavior than ECF.

Social neuroscience of child and adolescent depression

The social neuroscience of child and adolescent depression is inherently multidisciplinary. Depressive disorders beginning early in life can have serious developmental and functional consequences. Psychopathology research has described depression's defining clinical and contextual features, and intervention research has characterized its response to treatment and prevention programs. Neuroendocrine, electrophysiological, and neuroimaging studies have identified core neurobiological aspects of early-onset mood disorders. These areas are reviewed using a developmental social neuroscience perspective for integrating disparate observations. The paper introduces a dynamic adaptive systems framework, and it discusses hedonic capacity, stress sensitivity, ruminative self-focus, and attentional impairments as fundamental components of mood disorders.