The teen brain: insights from neuroimaging

Age differences in STDs, sexual behaviors, and correlates of risky sex among sexually experienced adolescent African-American females

OBJECTIVE

To explore age differences in factors associated with positive sexually transmitted diseases (STD) status among a sample of African-American adolescent females.

METHODS

Data were collected via ACASI from 701 African-American adolescent females (14-20 years) seeking services at reproductive health clinics. Adolescents provided self-collected vaginal swabs assayed using NAAT to assess the prevalence of three STDs.

RESULTS

Younger adolescents (14-17 years) had significantly higher rates of STDs than older adolescents (18-20 years), but older adolescents had significantly higher levels of STD-associated risk behavior. In controlled analysis, having a casual sex partner was the only variable significantly associated with a positive STD test for younger adolescents, and prior history of STD and higher impulsivity were significantly associated with testing STD positive among older adolescents.

CONCLUSIONS

These findings suggest that developmentally tailored STD/HIV prevention interventions are needed for younger and older subgroups of adolescent females to help reduce their risk of infection.

Transition from pediatric to adult renal services: a consensus statement by the International Society of Nephrology (ISN) and the International Pediatric Nephrology Association (IPNA)

The transfer of young patients from pediatric to adult renal care takes place after a transition process which involves both sides. It is important that it is individualized for each young person, focusing on self-management skills as well as assessing support structures. The consensus statement has been developed by the panel of adult and pediatric nephrologists and endorsed by the councils of both ISN and IPNA. It is hoped that the statement will provide a basis for the development of locally appropriate recommendations for clinical practice.

Lasting effects of chronic fluoxetine treatment on the late developing rat brain: age-dependent changes in the serotonergic neurotransmitter system assessed by pharmacological MRI

RATIONALE

With the growing prevalence of psychotropic drug prescriptions among children and adolescents, the need for studies on lasting effects of drug exposure on the developing brain rises. Fluoxetine is the only selective serotonin reuptake inhibitor (SSRI) officially registered to treat major depressive disorder in children. Although various (pre)clinical studies have assessed the (long-term) effects of fluoxetine exposure in the perinatal period and in adulthood, limited data is available on its effects on the developing brain later in life, i.e. during adolescence.

OBJECTIVE

The present study aimed at investigating the effects of age following chronic SSRI treatment on the central serotonin (5-HT) system. To this end, pharmacological MRI (phMRI) was performed in chronic fluoxetine-treated (5 mg/kg, oral gavage for 3 weeks) juvenile (PND25) and adult rats (PND65) after a 1-week washout period, using an acute fluoxetine challenge (5 mg/kg, i.v.) to trigger the 5-HT system.

RESULTS

We observed a diminished brain response to the acute challenge in adult treated animals when compared to control animals, whereas this response was increased in juvenile treated rats. As a result, a significant age by treatment interaction effect was seen in several (subcortical) 5-HT related brain regions.

CONCLUSION

An opposite effect of chronic fluoxetine treatment was seen in the developing brain compared to that in matured brain, as assessed non-invasively using phMRI. These findings most likely reflect neuronal imprinting effects of juvenile SSRI treatment and may underlie emotional disturbances seen in animals and children treated with this drug. Also, our findings suggest that phMRI might be ideally suited to study this important issue in the pediatric population.

Cognitive control reduces sensitivity to relational aggression among adolescent girls

Relational aggression is a type of aggression that aims to hurt others through relationships and includes behaviors such as gossip and ostracism. This type of aggression is very common among adolescent girls, and in its more intense forms has been linked with poor psychosocial outcomes, including depression and suicide. In the present study we investigated whether individual differences in sensitivity to relational aggression among adolescent girls predicted recruitment of neural networks associated with executive function and cognitive control. Neural response was measured using functional magnetic resonance imaging during an affect recognition task that included unfamiliar peer faces. A finding of relatively fewer reports of being victimized by relational aggression was associated with increased recruitment of bilateral dorsolateral prefrontal cortices as well as anterior and posterior cingulate cortices in response to the affect recognition task, as well as with greater competence on behavioral measures of executive function. Our results suggest that girls who are able to recruit specific frontal networks to improve cognitive and executive control are less sensitive to relational aggression.

A framework for the specificity of addictions

Research over the last two decades suggests that a wide range of substance and behavioral addictions may serve similar functions. Yet, co-occurrence of addictions has only been reported among a minority of addicts. "Addiction specificity" pertains to a phenomenon in which one pattern of addictive behaviors may be acquired whereas another is not. This paper presents the PACE model as a framework which might help explain addiction specificity. Pragmatics, attraction, communication, and expectation (PACE) variables are described, which may help give some direction to future research needs in this arena.

High folate intake is related to better academic achievement in Swedish adolescents

BACKGROUND

Adolescents are vulnerable to increased plasma total homocysteine (tHcy) and to insufficient folate status. Folate status and Hcy metabolism are linked to cognitive functions, but academic achievement by adolescents has not been studied in this respect.

OBJECTIVE

To assess a possible link between academic achievement in adolescents and tHcy and its determinants, dietary folate intake, MTHFR 677 TT homozygosity, and socioeconomic status (SES).

SUBJECTS AND METHODS

A study of 386 Swedish adolescents aged 15 years in whom plasma tHcy and MTHFR 677C →T genotype were assayed. The sum of school grades in 10 core subjects obtained in the final semester of compulsory 9 years of schooling was used as outcome measure of academic achievement. Lifestyle and SES data were obtained from questionnaires.

RESULTS

Academic achievement was strongly correlated to tertiles of tHcy (negatively; P = .023) and to tertiles of folate intake (positively; P < .001). Other significant predictors were gender, smoking, and SES (proxied by school, mother's education, and father's income). When these were controlled for, tertiles of folate intake (P < .002) but not tertiles of tHcy (P = .523) or MTHFR genotype remained significantly related to academic achievement.

CONCLUSION

Folate intake had a positive association with academic achievement in the 15-year-olds, which was not attenuated by SES or MTHFR 677 TT homozygosity. These results provide new information that points to the importance of keeping a closer watch on folate status in childhood and adolescence. They may also have direct implications for school meal provisions, school teaching programs, and information to parents.

Addiction, adolescence, and the integration of control and motivation

The likelihood of initiating addictive behaviors is higher during adolescence than during any other developmental period. The differential developmental trajectories of brain regions involved in motivation and control processes may lead to adolescents' increased risk taking in general, which may be exacerbated by the neural consequences of drug use. Neuroimaging studies suggest that increased risk-taking behavior in adolescence is related to an imbalance between prefrontal cortical regions, associated with executive functions, and subcortical brain regions related to affect and motivation. Dual-process models of addictive behaviors are similarly concerned with difficulties in controlling abnormally strong motivational processes. We acknowledge concerns raised about dual-process models, but argue that they can be addressed by carefully considering levels of description: motivational processes and top-down biasing can be understood as intertwined, co-developing components of more versus less reflective states of processing. We illustrate this with a model that further emphasizes temporal dynamics. Finally, behavioral interventions for addiction are discussed. Insights in the development of control and motivation may help to better understand - and more efficiently intervene in - vulnerabilities involving control and motivation.

Cognitive control in adolescence: neural underpinnings and relation to self-report behaviors

BACKGROUND

Adolescence is commonly characterized by impulsivity, poor decision-making, and lack of foresight. However, the developmental neural underpinnings of these characteristics are not well established.

METHODOLOGY/PRINCIPAL FINDINGS

To test the hypothesis that these adolescent behaviors are linked to under-developed proactive control mechanisms, the present study employed a hybrid block/event-related functional Magnetic Resonance Imaging (fMRI) Stroop paradigm combined with self-report questionnaires in a large sample of adolescents and adults, ranging in age from 14 to 25. Compared to adults, adolescents under-activated a set of brain regions implicated in proactive top-down control across task blocks comprised of difficult and easy trials. Moreover, the magnitude of lateral prefrontal activity in adolescents predicted self-report measures of impulse control, foresight, and resistance to peer pressure. Consistent with reactive compensatory mechanisms to reduced proactive control, older adolescents exhibited elevated transient activity in regions implicated in response-related interference resolution.

CONCLUSIONS/SIGNIFICANCE

Collectively, these results suggest that maturation of cognitive control may be partly mediated by earlier development of neural systems supporting reactive control and delayed development of systems supporting proactive control. Importantly, the development of these mechanisms is associated with cognitive control in real-life behaviors.

Age differences in strategic planning as indexed by the tower of London

The present study examined age differences in performance on the Tower of London, a measure of strategic planning, in a diverse sample of 890 individuals between the ages of 10 and 30. Although mature performance was attained by age 17 on relatively easy problems, performance on the hardest problems showed improvements into the early 20s. Furthermore, whereas age-related performance gains by children and adolescents (ages 10-17) on the hardest problems were partially mediated by maturational improvements in both working memory and impulse control, improved performance in adulthood (ages 18+) was fully mediated by late gains in impulse control. Findings support an emerging picture of late adolescence as a time of continuing improvement in planned, goal-directed behavior.

A three-year longitudinal functional magnetic resonance imaging study of performance monitoring and test-retest reliability from childhood to early adulthood

Previous cross-sectional functional magnetic resonance imaging studies have shown that performance monitoring functions continue to develop well into adolescence, associated with increased activation in brain regions important for cognitive control (prefrontal cortex, anterior cingulate cortex, and parietal cortex). To date, however, the development of performance monitoring has not yet been studied longitudinally, which leaves open the question whether changes can be detected within individuals over time. In the present study, human boys and girls, between ages 8 and 27 years, performed a child-friendly rule-switch task in the scanner on two occasions ∼3.5 years apart. Change versus stability was examined using two methods: (1) repeated-measures analyses and (2) test-retest reliabilities of blood oxygenation level-dependent responses. Results showed that with increasing age, participants performed better on the task. The changes in neural activation associated with the processing of performance feedback were, however, more reliably correlated with changes in performance than with age. Test-retest reliability was at least fair to good for adults and adolescents, but poor to fair for the youngest age group. Substantially more variability was observed in the pattern and magnitude of children compared with adults, which may be interpreted as proxy for developmental change. Together, the results show that (1) change within individuals is variable, and more so for children than for adolescents and adults, and (2) performance is a better predictor for change in neural activation over time. These findings set the stage for studying developmental change in the perspective of multiple predictors, rather than solely by divisions based on age groups.

Congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) due to P450c21 (21-hydroxylase deficiency) is a common autosomal recessive disorder. This disorder is due to mutations in the CYP21A2 gene which is located at chromosome 6p21. The clinical features reflect the magnitude of the loss of function mutations. Individuals with complete loss of function mutations usually present in the neonatal period. The clinical features of individuals with mild loss of function mutations are predominantly due to androgen excess rather than adrenal insufficiency leading to an ascertainment bias favoring diagnosis in females. Treatment goals include normal linear growth velocity and "on-time" puberty in affected children. For adolescent and adult women, treatment goals include regularization of menses, prevention of progression of hirsutism, and fertility. This article will review key aspects regarding pathophysiology, diagnosis, and treatment of CAH.

Repeat traumatic brain injury in the developing brain

The Center for Disease Control estimates that there are 1.7 million brain injuries in the US each year with 51% of these injuries occurring during periods of cerebral development. Among this population there is a growing population of individuals with repeat traumatic brain injury (RTBI). While the exact incidence is unknown, estimates range from 5.6 to 36% of the TBI population. This review summarizes the clinical problems/challenges and experimental research models that currently exist. It is intended to reveal the critical areas that need to be addressed so that age-relevant clinical management guidelines can be established to protect this population.

Brain imaging correlates of verbal working memory in children following traumatic brain injury

Neural correlates of working memory (WM) based on the Sternberg Item Recognition Task (SIRT) were assessed in 40 children with moderate-to-severe traumatic brain injury (TBI) compared to 41 demographically-comparable children with orthopedic injury (OI). Multiple magnetic resonance imaging (MRI) methods assessed structural and functional brain correlates of WM, including volumetric and cortical thickness measures on all children; functional MRI (fMRI) and diffusion tensor imaging (DTI) were performed on a subset of children. Confirming previous findings, children with TBI had decreased cortical thickness and volume as compared to the OI group. Although the findings did not confirm the predicted relation of decreased frontal lobe cortical thickness and volume to SIRT performance, left parietal volume was negatively related to reaction time (RT). In contrast, cortical thickness was positively related to SIRT accuracy and RT in the OI group, particularly in aspects of the frontal and parietal lobes, but these relationships were less robust in the TBI group. We attribute these findings to disrupted fronto-parietal functioning in attention and WM. fMRI results from a subsample demonstrated fronto-temporal activation in the OI group, and parietal activation in the TBI group, and DTI findings reflected multiple differences in white matter tracts that engage fronto-parietal networks. Diminished white matter integrity of the frontal lobes and cingulum bundle as measured by DTI was associated with longer RT on the SIRT. Across modalities, the cingulate emerged as a common structure related to performance after TBI. These results are discussed in terms of how different imaging modalities tap different types of pathologic correlates of brain injury and their relationship with WM.

Greater white and grey matter changes associated with early cannabis use in adolescent-onset schizophrenia (AOS)

BACKGROUND

Cannabis use is associated with a higher risk of schizophrenia, however, its specific long-term effect on the structure of the brain of adolescent-onset schizophrenic patients remains unclear.

AIMS

To study cognitive and structural (grey and white matter) changes in patients with adolescent-onset schizophrenia (AOS) with early cannabis use (CAN+ve) (more than 3 times/week for at least 6 months) and without cannabis use (CAN-ve) versus controls.

METHOD

An optimised voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) MRI study of 32 adolescents with DSM IV schizophrenia-16 CAN+ve and 16 CAN-ve, and 28 healthy adolescents.

RESULTS

Compared to CAN-ve subjects, CAN+ve subjects showed GM density loss in temporal fusiform gyrus, parahippocampal gyrus, ventral striatum, right middle temporal gyrus, insular cortex, precuneus, right paracingulate gyrus, dorsolateral prefrontal cortex, left postcentral gyrus, lateral occipital cortex and cerebellum. Similar group comparison showed decreased fractional anisotropy (FA) in particular in brain stem, internal capsule, corona radiata, superior and inferior longitudinal fasciculus in CAN+ve patients. No cognitive differences were apparent between CAN+ve and CAN-ve subjects, and both were impaired relative to controls.

CONCLUSION

Cannabis use in early adolescence increases WM and GM deficits in AOS, but does not appear to increase the cognitive deficit associated with this illness.

Adolescent initiation of licit and illicit substance use: Impact of intrauterine exposures and post-natal exposure to violence

Whether intrauterine exposures to alcohol, tobacco, marijuana, or cocaine predispose offspring to substance use in adolescence has not been established. We followed a sample of 149 primarily African American/African Caribbean, urban adolescents, recruited at term birth, until age 16 to investigate intrauterine cocaine exposure (IUCE). We found that in Kaplan-Meier analyses higher levels of IUCE were associated with a greater likelihood of initiation of any substance (licit or illicit), as well as marijuana and alcohol specifically. Adolescent initiation of other illicit drugs and cigarettes were analyzed only in the "any" summary variable since they were used too infrequently to analyze as individual outcomes. In Cox proportional hazard models controlling for intrauterine exposure to alcohol, tobacco, and marijuana and demographic and post-natal covariates, those who experienced heavier IUCE had a greater likelihood of initiation of any substance, and those with lighter intrauterine marijuana exposure had a greater likelihood of initiation of any substance as well as of marijuana specifically. Time-dependent higher levels of exposure to violence between ages of 8 and 16 were also robustly associated with initiation of any licit or illicit substance, and of marijuana, and alcohol particularly.

Behavioral and neural representation of emotional facial expressions across the lifespan

Humans' experience of emotion and comprehension of affective cues varies substantially across the lifespan. Work in cognitive and affective neuroscience has begun to characterize behavioral and neural responses to emotional cues that systematically change with age. This review examines work to date characterizing the maturation of facial expression comprehension, and dynamic changes in amygdala recruitment from early childhood through late adulthood while viewing facial expressions of emotion. Recent neuroimaging work has tested amygdala and prefrontal engagement in experimental paradigms mimicking real aspects of social interactions, which we highlight briefly, along with considerations for future research.

Pathophysiology of sports-related concussion: an update on basic science and translational research

CONTEXT

Concussions that occur during participation in athletic events affect millions of individuals each year. Although our understanding of the pathophysiology of concussion has grown considerably in recent years, much remains to be elucidated. This article reviews basic science and relevant translational clinical research regarding several aspects of concussion.

EVIDENCE ACQUISITION

A literature search was conducted using PubMed from 1966 to 2010, with an emphasis on work published within the past 10 years. Additional articles were identified from the bibliography of recent reviews.

RESULTS

Basic science and clinical data both indicate that there is a period of increased vulnerability to repeated injury following a concussion and that its duration is variable. Growing evidence indicates that postinjury activity is likely to affect recovery from brain injury. Data suggest that long-term sequelae may result from prior concussion-particularly, repeated injuries. The unique aspects of cerebral development may account for differences in the effects of concussion in children and adolescents when compared with adults.

CONCLUSIONS

The available pathophysiologic data from basic science and clinical studies have increased the evidence base for concussion management strategies-the approaches to which may differ between young athletes and adults.

Adolescent brain development and the risk for alcohol and other drug problems

Dynamic changes in neurochemistry, fiber architecture, and tissue composition occur in the adolescent brain. The course of these maturational processes is being charted with greater specificity, owing to advances in neuroimaging and indicate grey matter volume reductions and protracted development of white matter in regions known to support complex cognition and behavior. Though fronto-subcortical circuitry development is notable during adolescence, asynchronous maturation of prefrontal and limbic systems may render youth more vulnerable to risky behaviors such as substance use. Indeed, binge-pattern alcohol consumption and comorbid marijuana use are common among adolescents, and are associated with neural consequences. This review summarizes the unique characteristics of adolescent brain development, particularly aspects that predispose individuals to reward seeking and risky choices during this phase of life, and discusses the influence of substance use on neuromaturation. Together, findings in this arena underscore the importance of refined research and programming efforts in adolescent health and interventional needs.

Fronto-parietal regulation of media violence exposure in adolescents: a multi-method study

Adolescents spend a significant part of their leisure time watching TV programs and movies that portray violence. It is unknown, however, how the extent of violent media use and the severity of aggression displayed affect adolescents' brain function. We investigated skin conductance responses, brain activation and functional brain connectivity to media violence in healthy adolescents. In an event-related functional magnetic resonance imaging experiment, subjects repeatedly viewed normed videos that displayed different degrees of aggressive behavior. We found a downward linear adaptation in skin conductance responses with increasing aggression and desensitization towards more aggressive videos. Our results further revealed adaptation in a fronto-parietal network including the left lateral orbitofrontal cortex (lOFC), right precuneus and bilateral inferior parietal lobules, again showing downward linear adaptations and desensitization towards more aggressive videos. Granger causality mapping analyses revealed attenuation in the left lOFC, indicating that activation during viewing aggressive media is driven by input from parietal regions that decreased over time, for more aggressive videos. We conclude that aggressive media activates an emotion-attention network that has the capability to blunt emotional responses through reduced attention with repeated viewing of aggressive media contents, which may restrict the linking of the consequences of aggression with an emotional response, and therefore potentially promotes aggressive attitudes and behavior.

Framework for sex differences in adolescent neurobiology: a focus on cannabinoids

This review highlights the salient findings that have furthered our understanding of how sex differences are initiated during development and maintained throughout life. First we discuss how gonadal steroid hormones organize the framework for sex differences within critical periods of development-namely, during those exposures which occur in utero and post-partum, as well as those which occur during puberty. Given the extensive precedence of sex differences in cannabinoid-regulated biology, we then focus on the disparities within the endogenous cannabinoid system, as well as those observed with exogenously administered cannabinoids. We start with how the expression of cannabinoid CB(1) receptors is regulated throughout development. This is followed by a discussion of differential vulnerability to the pathological sequelae stemming from cannabinoid exposure during adolescence. Next we talk about sex differences in the interactions between cannabinoids and other drugs of abuse, followed by the organizational and activational roles of gonadal steroids in establishing and maintaining the sex dependence in the biological actions of cannabinoids. Finally, we discuss ways to utilize this knowledge to strategically target critical developmental windows of vulnerability/susceptibility and thereby implement more effective therapeutic interventions for afflictions that may be more prevalent in one sex vs. the other.

Adolescent development and risk of injury: using developmental science to improve interventions

In adolescence, there is a complex interaction among physical, cognitive, and psychosocial developmental processes, culminating in greater risk-taking and novelty-seeking. Concurrently, adolescents face an increasingly demanding environment, which results in heightened vulnerability to injury. In this paper, we provide an overview of developmental considerations for adolescent injury interventions based on developmental science, including findings from behavioural neuroscience and psychology. We examine the role that typical developmental processes play in the way adolescents perceive and respond to risk and how this integrated body of developmental research adds to our understanding of how to do injury prevention with adolescents. We then highlight strategies to improve the translation of developmental research into adolescent injury prevention practice, calling on examples of existing interventions including graduated driver licensing.

Structural covariance in the cortex of very preterm adolescents: a voxel-based morphometry study

On the basis of findings in normative samples that different cortical brain regions covary in gray matter volume, most likely as a result of mutually trophic influences during cortical development, we aimed to study whether patterns of covariation in regional gray matter, i.e., structural covariance, differed between adolescents who were born very preterm and full-term controls. Optimized voxel-based morphometry was used to study structural magnetic resonance imaging scans from 218 very preterm adolescents (gestational age <33 weeks) and 127 controls at 14-15 years of age. Local gray matter volumes were obtained for 18 regions of interest involved in sensorimotor and higher-order cognitive functions. These were then used to predict local volumes in the remaining areas of the cortex, with total gray matter volume, age and gender used as confounding variables. Very preterm adolescents compared with controls demonstrated differential (i.e., both increased and decreased) structural covariance between medial, frontal and cingulate gyri, caudate nucleus, thalamus, primary visual cortex, cerebellum and several other cortical and subcortical regions of the cortex. These findings support previous research indicating that preterm birth is associated with altered cortical development, and suggest that developmental changes in one brain region may result in a cascade of alterations in multiple regions.

A cross-sectional survey of compliance with national guidance for alcohol consumption by children: measuring risk factors, protective factors and social norms for excessive and unsupervised drinking

BACKGROUND

The Chief Medical Officer for England has developed the first guidance in England and some of the first internationally on alcohol consumption by children. Using the most recent iteration of a large biennial survey of schoolchildren we measure the extent to which young people's drinking fell within the guidelines just prior to their introduction and the characteristics of individuals whose drinking does not; how alcohol related harms relate to compliance; and risk factors associated with behaving outside of the guidance.

METHODS

A cross-sectional survey was conducted utilising a self-completed questionnaire with closed questions. A total of 11,879 schoolchildren, aged 15-16 years, from secondary schools in North West England participated in the study. Data were analysed using chi square and conditional logistic regression.

RESULTS

Alcohol consumption is an established norm by age 15 years (81.3%). Acute alcohol related violence, regretted sex and forgetfulness were experienced by significantly fewer children drinking within the guidance (than outside of it). Over half of drinkers (54.7%) reported routinely drinking more heavily than guidance suggests (here ≥ 5 drinks/session ≥ 1 month), or typically drinking unsupervised at home or at a friend's home when parents were absent (57.4%). Both behaviours were common across all deprivation strata. Children with greater expendable incomes were less likely to consume within guidance and reported higher measures for unsupervised, frequent and heavy drinking. Although drinking due to peer pressure was associated with some measures of unsupervised drinking, those reporting that they drank out of boredom were more likely to report risk-related drinking behaviours outside of the guidance.

CONCLUSIONS

Successful implementation of guidance on alcohol consumption for children could result in substantial reductions in existing levels of alcohol related harms to young people. However, prolonged social marketing, educational and parental interventions will be required to challenge established social norms in heavy and unsupervised child drinking across all social strata. Policy measures to establish a minimum price for alcohol and provide children with entertaining alternatives to alcohol should also increase compliance with guidance.

Heritability of delay discounting in adolescence: a longitudinal twin study

Delay discounting (DD) refers to the preference for smaller immediate rewards over larger but delayed rewards, and is considered to be a distinct component of a broader "impulsivity" construct. Although greater propensity for discounting the value of delayed gratification has been associated with a range of problem behaviors and substance abuse, particularly in adolescents, the origins of individual differences in DD remain unclear. We examined genetic and environmental influences on a real-life behavioral measure of DD using a longitudinal twin design. Adolescent participants were asked to choose between a smaller ($7) reward available immediately and a larger ($10) reward to be received in 7 days. Biometrical genetic analysis using linear structural equation modeling showed significant heritability of DD at ages 12 and 14 (30 and 51%, respectively) and suggested that the same genetic factors influenced the trait at both ages. DD was significantly associated with symptoms of conduct disorder, attention deficit hyperactivity disorder, substance use, and with higher novelty seeking and poor self-regulation. This study provides the first evidence for heritability of DD in humans and suggests that DD can be a promising endophenotype for genetic studies of addiction and externalizing disorders.

Current lifestyle of young adults after liver transplantation during childhood

The authors studied the psychosocial adjustment of pediatric liver transplant (LT) recipients reaching adulthood. The study comprised phone interviews of 116 volunteers aged 17-33 years. Results were compared to those for healthy peers and 65 patients who were eligible for inclusion but did not participate. Participants' median age at LT was 6 years and the median period since LT was 15 years. Of the 116 participants, 76% considered their quality of life as good or very good. Seventy-five patients (65%) were attending schools, 27 of whom were 2 years or more below the age-appropriate level. Of the remaining 41 patients, 26 had a job and 15 were unemployed. Poor compliance with medications was reported by 52 patients (45%). Alcohol consumption was lower than in the reference population (p < 0.001). Anxiety, loneliness and negative thoughts were expressed by 53, 84 and 47% of the participants, respectively. Thirteen patients (11%) were being cared for by psychologists or psychiatrists. The 65 nonparticipants had greater psychological problems than the participants, and a lower educational level. In conclusion, after LT in early life, most patients displayed psychological vulnerability during early adulthood. The educational level of patients was lower than that of theirs peers.

Effects of exogenous agents on brain development: stress, abuse and therapeutic compounds

The range of exogenous agents likely to affect, generally detrimentally, the normal development of the brain and central nervous system defies estimation although the amount of accumulated evidence is enormous. The present review is limited to certain types of chemotherapeutic and "use-and-abuse" compounds and environmental agents, exemplified by anesthetic, antiepileptic, sleep-inducing and anxiolytic compounds, nicotine and alcohol, and stress as well as agents of infection; each of these agents have been investigated quite extensively and have been shown to contribute to the etiopathogenesis of serious neuropsychiatric disorders. To greater or lesser extent, all of the exogenous agents discussed in the present treatise have been investigated for their influence upon neurodevelopmental processes during the period of the brain growth spurt and during other phases uptill adulthood, thereby maintaining the notion of critical phases for the outcome of treatment whether prenatal, postnatal, or adolescent. Several of these agents have contributed to the developmental disruptions underlying structural and functional brain abnormalities that are observed in the symptom and biomarker profiles of the schizophrenia spectrum disorders and the fetal alcohol spectrum disorders. In each case, the effects of the exogenous agents upon the status of the affected brain, within defined parameters and conditions, is generally permanent and irreversible.

The medical home concept and congenital adrenal hyperplasia: a comfortable habitat!

Patient-centered interdisciplinary health care for children with chronic medical disorders represents an evolution from the traditional “stop and go” treatment for acute illnesses. This model for health care delivery has been called the “medical home,” a concept that was originally developed in pediatrics for the care of children with special needs. Patient and family-centered, comprehensive, interdisciplinary, culturally effective, and readily accessible health care delivery is desirable for the care of children with congenital adrenal hyperplasia. As children with congenital adrenal hyperplasia (CAH) become adolescents and young adults, transfer of this health care delivery model to adult endocrinologists is appropriate.

Invited commentary: understanding brain mechanisms of pain processing in adolescents' non-suicidal self-injury

Whereas non-suicidal self injury (NSSI) is reported in 13-23% of adolescents and is an increasingly studied topic, there has been little investigation into the pathophysiology behind self-injury. This commentary examines recent research into pain and emotional distress to discuss implications for the manner we should understand, research, and treat NSSI in the future. Research indicates that adolescents may be particularly vulnerable to NSSI behaviors due to neurodevelopmental changes in the processing of distress and pain. Additionally, emotional distress and physical pain neural pathways may have been altered in these individuals, leading to the development of NSSI behaviors during adolescence when changes in ongoing brain development may lead to further emotional dysregulation and poor impulse control. Further studies that directly characterize the relationship between emotional distress and physical pain in adolescence, as well as the neural differences between self-injurers and non-self-injurers, are needed.

Cerebral and cerebellar volume loss in children and adolescents with systemic lupus erythematosus: a review of clinically acquired brain magnetic resonance imaging

OBJECTIVE

Cerebral atrophy is a prominent feature in adults with systemic lupus erythematosus (SLE). We assessed cerebral and cerebellar volume loss on clinically acquired brain magnetic resonance imaging (MRI) scans of children and adolescents with SLE.

METHODS

We abstracted information on disease course for patients who underwent clinical brain MRI during the period 2002-2008. We completed qualitative assessments of volume loss and measured corpus callosum thickness and ventricular enlargement for patients with lupus and controls.

RESULTS

Forty-nine children underwent brain MRI during the review period due to clinical indications. The lupus cohort was predominantly female and ethnically diverse. Mean age at imaging was 15.3 +/- 2.6 years and mean disease duration was 30.6 +/- 33.3 months. Findings suggestive of cerebral and cerebellar volume loss were seen respectively in 89.8% and 91.8% of lupus patients. Cerebral volume loss was moderate or severe in 26.5% of children. Cerebellar volume loss was moderate in 20.4% of these patients. Linear measurement means reflected corpus callosum thinning and ventricular enlargement in lupus patients. Volume loss was observed in newly diagnosed patients prior to corticosteroid use. Disease duration and corticosteroid use did not predict the severity of volume loss. There were statistically significant differences in linear imaging measurements comparing lupus patients to 14 similar-age controls.

CONCLUSION

Regional volume loss was observed in most adolescents with lupus undergoing clinical brain MRI scans. As in other pediatric conditions with inflammatory or vascular etiologies, these findings may be reflecting disease-associated neuronal loss and not solely the effects of corticosteroid.

Alcohol use by youth and adolescents: a pediatric concern

Alcohol use continues to be a major problem from preadolescence through young adulthood in the United States. Results of recent neuroscience research have substantiated the deleterious effects of alcohol on adolescent brain development and added even more evidence to support the call to prevent and reduce underaged drinking. Pediatricians should be knowledgeable about substance abuse to be able to recognize risk factors for alcohol and other substance abuse among youth, screen for use, provide appropriate brief interventions, and refer to treatment. The integration of alcohol use prevention programs in the community and our educational system from elementary school through college should be promoted by pediatricians and the health care community. Promotion of media responsibility to connect alcohol consumption with realistic consequences should be supported by pediatricians. Additional research into the prevention, screening and identification, brief intervention, and management and treatment of alcohol and other substance use by adolescents continues to be needed to improve evidence-based practices.

Neurochemistry of drug action: insights from proton magnetic resonance spectroscopic imaging and their relevance to addiction

Proton magnetic resonance spectroscopy ((1)H MRS) is a noninvasive imaging technique that permits measurement of particular compounds or metabolites within the tissue of interest. In the brain, (1)H MRS provides a snapshot of the neurochemical environment within a defined volume of interest. A search of the literature demonstrates the widespread utility of this technique for characterizing tumors, tracking the progress of neurodegenerative disease, and for understanding the neurobiological basis of psychiatric disorders. As of relatively recently, (1)H MRS has found its way into substance abuse research, and it is beginning to become recognized as a valuable complement in the brain imaging toolbox that also contains positron emission tomography, single-photon-emission computed tomography, and functional magnetic resonance imaging. Drug abuse studies using (1)H MRS have identified several biochemical changes in the brain. The most consistent alterations across drug class were reductions in N-acetylaspartate and elevations in myo-inositol, whereas changes in choline, creatine, and amino acid transmitters also were abundant. Together, the studies discussed herein provide evidence that drugs of abuse may have a profound effect on neuronal health, energy metabolism and maintenance, inflammatory processes, cell membrane turnover, and neurotransmission, and these biochemical changes may underlie the neuropathology within brain tissue that subsequently gives rise to the cognitive and behavioral impairments associated with drug addiction.

Pubertal maturation and programming of hypothalamic-pituitary-adrenal reactivity

Modifications in neuroendocrine function are a hallmark of pubertal development. These changes have many short- and long-term implications for the physiological and neurobehavioral function of an individual. The purpose of the present review is to discuss our current understanding of how pubertal development and stress interact to affect the hypothalamic-pituitary-adrenal (HPA) axis, the major neuroendocrine axis that controls the hormonal stress response. A growing body of literature indicates that puberty is marked by dramatic transitions in stress reactivity. Moreover, recent studies indicate that exposure to stressors during pubertal maturation may result in enduring changes in HPA responsiveness in adulthood. As puberty is marked by a substantial increase in many stress-related psychological and physiological disorders (e.g., depression, anxiety, drug abuse), it is essential to understand the factors that regulate and modulate HPA function during this crucial period of development.

Transition of care to adult services for pediatric solid-organ transplant recipients

The importance of transition to adult health care for young people with chronic conditions is increasingly recognized. Ensuring effective engagement with adult services for adolescents and young-adult solid-organ transplant recipients is as critical for immediate graft survival as it is for their future health and well-being. This article (1) examines the definitions of adolescence and emerging adulthood and some of the challenges of these phases of life, (2) discusses elements that may influence motivation and engagement and enhance communication and adherence for adolescents and young adults, (3) highlights important areas in education, vocational planning, and quality of life for transplant recipients, (4) reviews tasks and challenges during the transition, and (5) provides specific transition recommendations, for both transplant health care professionals and for primary care providers practicing outside transplant centers.

Longitudinal characterization of white matter maturation during adolescence

BACKGROUND

Late adolescence is comprised of considerable developmental transitions, though brain maturational changes during this period are subtle and difficult to quantitatively evaluate from standard brain imaging acquisitions. To date, primarily cross-sectional studies have characterized typical developmental changes during adolescence, but these processes need further description within a longitudinal framework.

METHOD

To assess the developmental trajectory of typical white matter development, we examined 22 healthy adolescents with serial diffusion tensor images (DTI) collected at a mean age of 17.8 years and 16-months later. Diffusion parameters fractional anisotropy, and mean, radial, and axial diffusivity were subjected to whole-brain voxelwise time point comparisons using tract-based spatial statistics.

RESULTS

At follow-up, adolescents showed a significant change (>or=153 contiguous voxels each at p<0.01) in diffusion properties, including in bilateral superior longitudinal fasciculi, superior corona radiata, anterior thalamic radiations, and posterior limb of the internal capsule. Overall, correlations with cognitive performances suggested behavioral improvement corresponding with white matter changes.

CONCLUSION

These longitudinal DTI findings support continued microstructural change in white matter during late adolescence, and suggest ongoing refinement of projection and association fibers into early adulthood.

The changing face of emotion: age-related patterns of amygdala activation to salient faces

The present study investigated age-related differences in the amygdala and other nodes of face-processing networks in response to facial expression and familiarity. fMRI data were analyzed from 31 children (3.5-8.5 years) and 14 young adults (18-33 years) who viewed pictures of familiar (mothers) and unfamiliar emotional faces. Results showed that amygdala activation for faces over a scrambled image baseline increased with age. Children, but not adults, showed greater amygdala activation to happy than angry faces; in addition, amygdala activation for angry faces increased with age. In keeping with growing evidence of a positivity bias in young children, our data suggest that children find happy faces to be more salient or meaningful than angry faces. Both children and adults showed preferential activation to mothers' over strangers' faces in a region of rostral anterior cingulate cortex associated with self-evaluation, suggesting that some nodes in frontal evaluative networks are active early in development. This study presents novel data on neural correlates of face processing in childhood and indicates that preferential amygdala activation for emotional expressions changes with age.

Sleep actigraphy pattern and behavioral/emotional difficulties in kindergarten children: association with hypothalamic-pituitary-adrenocortical (HPA) activity

BACKGROUND

Various studies of adult endocrinology and sleep show close connections between poor sleep quality, deterioration of the HPA axis and negative psychological characteristics. However, the extent to which these associations may have already emerged and developed in childhood remains unclear.

METHODS

A total of 82 preschoolers (age 4.91+/-0.48) underwent activity monitoring for seven consecutive days and nights, wearing a digital movement-measuring instrument. Additionally, on the first and on the last morning of sleep registration, the activity of the HPA axis was assessed via the amount of cortisol in the saliva. Psychological and behavioral assessments were also made.

RESULTS

Three sub-groups of good (22%), normal (58.5%) and poor (19.5%) sleepers were distinguished. Poor sleep patterns were associated with higher HPA activity and with behavioral/emotional difficulties.

CONCLUSIONS

The interplay between unfavorable sleep patterns, deterioration of the HPA axis and behavioral/emotional difficulties is already apparent in pre-school children.