The teen brain: insights from neuroimaging

Ongoing neural development of affective theory of mind in adolescence

Affective Theory of Mind (ToM), an important aspect of ToM, involves the understanding of affective mental states. This ability is critical in the developmental phase of adolescence, which is often related with socio-emotional problems. Using a developmentally sensitive behavioral task in combination with functional magnetic resonance imaging, the present study investigated the neural development of affective ToM throughout adolescence. Eighteen adolescent (ages 12-14 years) and 18 young adult women (aged 19-25 years) were scanned while evaluating complex affective mental states depicted by actors in video clips. The ventromedial prefrontal cortex (vmPFC) showed significantly stronger activation in adolescents in comparison to adults in the affective ToM condition. Current results indicate that the vmPFC might be involved in the development of affective ToM processing in adolescence.

Long-term effects of chronic intermittent ethanol exposure in adolescent and adult rats: radial-arm maze performance and operant food reinforced responding

Background

Adolescence is not only a critical period of late-stage neurological development in humans, but is also a period in which ethanol consumption is often at its highest. Given the prevalence of ethanol use during this vulnerable developmental period we assessed the long-term effects of chronic intermittent ethanol (CIE) exposure during adolescence, compared to adulthood, on performance in the radial-arm maze (RAM) and operant food-reinforced responding in male rats.

Methodology/Principal Findings

Male Sprague Dawley rats were exposed to CIE (or saline) and then allowed to recover. Animals were then trained in either the RAM task or an operant task using fixed- and progressive- ratio schedules. After baseline testing was completed all animals received an acute ethanol challenge while blood ethanol levels (BECs) were monitored in a subset of animals. CIE exposure during adolescence, but not adulthood decreased the amount of time that animals spent in the open portions of the RAM arms (reminiscent of deficits in risk-reward integration) and rendered animals more susceptible to the acute effects of an ethanol challenge on working memory tasks. The operant food reinforced task showed that these effects were not due to altered food motivation or to differential sensitivity to the nonspecific performance-disrupting effects of ethanol. However, CIE pre-treated animals had lower BEC levels than controls during the acute ethanol challenges indicating persistent pharmacokinetic tolerance to ethanol after the CIE treatment. There was little evidence of enduring effects of CIE alone on traditional measures of spatial and working memory.

Conclusions/Significance

These effects indicate that adolescence is a time of selective vulnerability to the long-term effects of repeated ethanol exposure on neurobehavioral function and acute ethanol sensitivity. The positive and negative findings reported here help to further define the nature and extent of the impairments observed after adolescent CIE and provide direction for future research.

Effects of moderate to severe traumatic brain injury on anticipating consequences of actions in adolescents: a preliminary study

For this pilot study, we compared performance of 15 adolescents with moderate-severe traumatic brain injury (TBI) to that of 13 typically developing (TD) adolescents in predicting social actions and consequences for avatars in a virtual microworld environment faced with dilemmas involving legal or moral infractions. Performance was analyzed in relation to cortical thickness in brain regions implicated in social cognition. Groups did not differ in number of actions predicted nor in reasons cited for predictions when presented only the conflict situation. After viewing the entire scenario, including the choice made by the avatar, TD and TBI adolescents provided similar numbers of short-term consequences. However, TD adolescents provided significantly more long-term consequences (p = .010). Additionally, for the Overall qualitative score, TD adolescents' responses were more likely to reflect the long-term impact of the decision made (p = .053). Groups differed in relation of the Overall measure to thickness of right medial prefrontal cortex/frontal pole and precuneus, with stronger relations for the TD group (p < .01). For long-term consequences, the relations to the posterior cingulate, superior medial frontal, and precentral regions, and to a lesser extent, the middle temporal region, were stronger for the TBI group (p < .01).

Self-directedness and cooperativeness, psychosocial dysfunction and suffering in ESSENCE

Background. The acronym ESSENCE (Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations) highlights that children seeking clinical treatment are often multiply impaired, thus requiring treatment from several specialties. The aim was to map and relate, on a population level, ESSENCE to two salient predictors of health and adaptation to adversities, namely, Self-Directedness and Cooperativeness and also to dysfunction and suffering. Methods. Participants were twins (N = 1892) aged 9 or 12 whose parents were interviewed with the Autism-Tics, ADHD and other Comorbidities inventory (A-TAC), and the Junior Temperament and Character Inventory (J-TCI). The A-TAC was first used to discern four ESSENCE-related screening diagnoses: autism spectrum disorders, attention deficit hyperactivity disorder, learning disabilities, and developmental coordination disorder; second, to quantify dysfunction and suffering in important social areas. Results. ESSENCE symptoms were continuously and categorically associated with deficiency in Self-Directedness and Cooperativeness and higher ratings of dysfunction and suffering. The impact of ESSENCE symptoms on these measures of mental health was found in a milder form in about 16% of all children and in a severe form in about 2%. Conclusion. Therapeutic interventions focusing on Self-Directedness and Cooperativeness might provide a novel method for child psychiatry in its approach to ESSENCE.

Demolishing the competition: the longitudinal link between competitive video games, competitive gambling, and aggression

The majority of research on the link between video games and aggression has focused on the violent content in games. In contrast, recent experimental research suggests that it is video game competition, not violence, that has the greatest effect on aggression in the short-term. However, no researchers have examined the long-term relationship between video game competition and aggression. In addition, if competition in video games is a significant reason for the link between video game play and aggression, then other competitive activities, such as competitive gambling, also may predict aggression over time. In the current study, we directly assessed the socialization (competitive video game play and competitive gambling predicts aggression over time) versus selection hypotheses (aggression predicts competitive video game play and competitive gambling over time). Adolescents (N = 1,492, 50.8 % female) were surveyed annually from Grade 9 to Grade 12 about their video game play, gambling, and aggressive behaviors. Greater competitive video game play and competitive gambling predicted higher levels of aggression over time, after controlling for previous levels of aggression, supporting the socialization hypothesis. The selection hypothesis also was supported, as aggression predicted greater competitive video game play and competitive gambling over time, after controlling for previous competitive video game play and competitive gambling. Our findings, taken together with the fact that millions of adolescents play competitive video games every day and that competitive gambling may increase as adolescents transition into adulthood, highlight the need for a greater understanding of the relationship between competition and aggression.

Adolescent cocaine exposure causes enduring macroscale changes in mouse brain structure

Cocaine dependence is associated with abnormalities in brain structure in humans. However, it is unclear whether these differences in brain structure predispose an individual to drug use or are a result of cocaine's action on the brain. This study investigates the impact of chronic cocaine exposure on brain structure and drug-related behavior in mice. Specifically, mice received daily cocaine or saline injections for 20 d during two developmental time periods: adolescence (27-46 d old) and young adulthood (60-79 d old). Following 30 d of abstinence, either fixed brain T2 weighted magnetic resonance images were acquired on a 7 T scanner at 32 μm isotropic voxel dimensions or mice were assessed for sensitization to the locomotor stimulant effects of cocaine. Three automated techniques (deformation-based morphometry, striatum shape analysis, and cortical thickness assessment) were used to identify population differences in brain structure in cocaine-exposed versus saline-exposed mice. We found that cocaine induced changes in brain structure, and these were most pronounced in mice exposed to cocaine during adolescence. Many of these changes occurred in brain regions previously implicated in addiction including the nucleus accumbens, striatum, insular cortex, orbitofrontal cortex, and medial forebrain bundle. Furthermore, exposure to the same cocaine regimen caused sensitization to the locomotor stimulant effects of cocaine, and these effects were again more pronounced in mice exposed to cocaine during adolescence. These results suggest that altered brain structure following 1 month of abstinence may contribute to these persistent drug-related behaviors, and identify cocaine exposure as the cause of these morphological changes.

Changes in alcohol-related brain networks across the first year of college: a prospective pilot study using fMRI effective connectivity mapping

The upsurge in alcohol use that often occurs during the first year of college has been convincingly linked to a number of negative psychosocial consequences and may negatively affect brain development. In this longitudinal functional magnetic resonance imaging (fMRI) pilot study, we examined changes in neural responses to alcohol cues across the first year of college in a normative sample of late adolescents. Participants (N=11) were scanned three times across their first year of college (summer, first semester, second semester), while completing a go/no-go task in which images of alcoholic and non-alcoholic beverages were the response cues. A state-of-the-art effective connectivity mapping technique was used to capture spatiotemporal relations among brain regions of interest (ROIs) at the level of the group and the individual. Effective connections among ROIs implicated in cognitive control were greatest at the second assessment (when negative consequences of alcohol use increased), and effective connections among ROIs implicated in emotion processing were lower (and response times were slower) when participants were instructed to respond to alcohol cues compared to non-alcohol cues. These preliminary findings demonstrate the value of a prospective effective connectivity approach for understanding adolescent changes in alcohol-related neural processes.

Decomposing developmental differences in probabilistic feedback learning: a combined performance and heart-rate analysis

Learning on the basis of outcome feedback shows pronounced developmental changes, however, much is still unknown about its underlying processes. In the current study, we aimed at decomposing how value updating, feedback monitoring and executing behavioral control contribute to children's probabilistic feedback learning. Children (ages 8-9), young adolescents (ages 11-13) and young adults (ages 18-24), performed two probabilistic feedback tasks: one required building a value representation on the basis of feedback (noninformed task), while in the other value representations were explicitly presented (informed task). Heart-rate was recorded to augment performance measures of feedback processing. We observed substantial developmental differences in heart-rate responses toward feedback in the noninformed task. Adult's heart-rate slowed more to negative compared to positive feedback relative to the children and young adolescents. In contrast, in the informed task all age groups showed larger heart-rate slowing toward negative compared to positive feedback. These results indicate that children are not impaired in monitoring probabilistic feedback per se, but have a specific deficit in building a task-appropriate value representation on the basis of probabilistic feedback.

Alcohol intoxications during adolescence increase motivation for alcohol in adult rats and induce neuroadaptations in the nucleus accumbens

Adolescent alcohol binge drinking constitutes a major vulnerability factor to develop alcoholism. However, mechanisms underlying this susceptibility remain unknown. We evaluated the effect of adolescent binge-like ethanol intoxication on vulnerability to alcohol abuse in Sprague-Dawley rats. To model binge-like ethanol intoxication, every 2 days, rats received an ethanol injection (3.0 g/kg) for 2 consecutive days across 14 days either from postnatal day 30 (PND30) to 43 (early adolescence) or from PND 45 to PND 58 (late adolescence). In young adult animals, we measured free ethanol consumption in the two-bottle choice paradigm, motivation for ethanol in the operant self-administration task and both ethanol's rewarding and aversive properties in the conditioned place preference (CPP) and taste aversion (CTA) paradigms. While intermittent ethanol intoxications (IEI) during late adolescence had no effect on free-choice 10% ethanol consumption, we found that IEI during early adolescence promoted free-choice 10% ethanol consumption, enhanced motivation for ethanol in the self-administration paradigm and induced a loss of both ethanol-induced CPP and CTA in young adults. No modification in either sucrose self-administration or amphetamine-induced CPP was observed. As the nucleus accumbens (Nac) is particularly involved in addictive behavior, we analyzed IEI-induced long-term neuroadaptations in the Nac using c-Fos immunohistochemistry and an array of neurotransmission-related genes. This vulnerability to ethanol abuse was associated with a lower c-Fos immunoreactivity in the Nac and enduring alterations of the expression of Penk and Slc6a4, 2 neurotransmission-related genes that have been shown to play critical roles in the behavioral effects of ethanol and alcoholism.

Care of adolescent parents and their children

Teen pregnancy and parenting remain an important public health issue in the United States and the world, and many children live with their adolescent parents alone or as part of an extended family. A significant proportion of teen parents reside with their family of origin, significantly affecting the multigenerational family structure. Repeated births to teen parents are also common. This clinical report updates a previous policy statement on care of the adolescent parent and their children and addresses medical and psychosocial risks specific to this population. Challenges unique to teen parents and their children are reviewed, along with suggestions for the pediatrician on models for intervention and care.

Nucleus Accumbens Volume Is Associated with Frequency of Alcohol Use among Juvenile Justice-Involved Adolescents

Differential neural development of structures associated with reward and control systems may underlie risky behavior in adolescence. The nucleus accumbens and orbitofrontal cortex (OFC) have been implicated in substance use behavior, although structural studies have yet to explore specific relationships between nucleus accumbens and OFC volumes and alcohol use in adolescence. High resolution structural MRI scans and assessments of recent alcohol use and lifetime substance use were collected in a sample of 168 juvenile justice-involved adolescents to explore whether gray matter volumes were associated with past 3-month quantity and frequency of alcohol use. Gray matter volumes were not associated with average quantity of alcohol use. Accumbens volume was positively associated with past 3-month frequency of drinking, and OFC volume was negatively associated with drinking frequency. Results may suggest that structural differences in regions related to reward and control processing may contribute to risk behavior in adolescence.

Stress and the developing adolescent brain

Adolescence is a time of continued brain maturation, particularly in limbic and cortical regions, which undoubtedly plays a role in the physiological and emotional changes coincident with adolescence. An emerging line of research has indicated that stressors experienced during this crucial developmental stage may affect the trajectory of this neural maturation and contribute to the increase in psychological morbidities, such as anxiety and depression, often observed during adolescence. In this review, we discuss the short- and long-term effects of periadolescent stress exposure on the structure and function of the brain. More specifically, we examine how stress at prepubertal and early adolescent stages of development affects the morphological plasticity of limbic and cortical brain regions, as well as the enduring effects of adolescent stress exposure on these brain regions in adulthood. We suggest that, due to a number of converging factors during this period of maturation, the adolescent brain may be particularly sensitive to stress-induced neurobehavioral dysfunctions with important consequences on an individual's immediate and long-term health and well-being.

Personality traits, quality of life and perceived health in adolescents with congenital heart disease

This study investigated how the big five personality traits were related to quality of life and perceived health in adolescents with congenital heart disease (CHD). Adolescents with CHD were selected from the database of paediatric and congenital cardiology of the University Hospitals Leuven. A total of 366 adolescents (15-20 years) participated; 364 were matched on sex and age with community controls. Adolescents' personality was assessed using the quick big five, quality of life was measured using a linear analogue scale and several domains of perceived health were assessed using the paediatric quality of life inventory. Adolescents with CHD displayed similar big five levels as controls, except for a lower score on extraversion. Whereas disease-specific domains of perceived health were mainly related to emotional stability, several traits contributed to patients' quality of life and generic perceived health. Hence, the present findings demonstrate that the Big Five is a valuable framework for examining linkages between personality and disease adaptation in chronic disease populations. Moreover, these findings underscore the importance of examining patients' personality to shed light on their daily functioning. Future research should explore potential mechanisms detailing how personality influences disease adaptation over time in these patients.

A mouse model for adolescent alcohol abuse: stunted growth and effects in brain

BACKGROUND

Adolescent alcohol abuse remains a serious public health concern, with nearly a third of high school seniors reporting heavy drinking in the previous month.

METHODS

Using the high ethanol-consuming C57BL/6J mouse strain, we examined the effects of ethanol (3.75 g/kg, IP, daily for 45 days) on body weight and brain region mass (cerebral cortex, cerebellum, corpus callosum) during peri-adolescence (postnatal day [P]25 to 70) or adulthood (P180 to 225) of both males and females.

RESULTS

In control peri-adolescent animals, body weight gain was greater in males compared with females. In the peri-adolescent exposure group, ethanol significantly reduced body weight gain to a similar extent in both male and female mice (82 and 84% of controls, respectively). In adult animals, body weight gain was much less than that of the peri-adolescent mice, with ethanol having a small but significant effect in males but not females. Between the control peri-adolescent and adult cohorts (measurements taken at P70 and 225, respectively), there were no significant differences in the mass of the cerebral cortex or the cerebellum from either male or female mice, although the rostro-caudal length of the corpus callosum increased slightly but significantly (6.1%) between these time points.

CONCLUSIONS

Ethanol treatment significantly reduced the mass of the cerebral cortex in peri-adolescent (-3.1%), but not adult, treated mice. By contrast, ethanol significantly reduced the length of the corpus callosum in adult (-5.4%), but not peri-adolescent, treated mice. Future studies at the histological level may yield additional details concerning ethanol and the peri-adolescent brain.

The interaction of disrupted type II neuregulin 1 and chronic adolescent stress on adult anxiety- and fear-related behaviors

The incidence of anxiety, mood, substance abuse disorders and schizophrenia increases during adolescence. Epidemiological evidence confirms that exposure to stress during sensitive periods of development can create vulnerabilities that put genetically predisposed individuals at increased risk for psychiatric disorders. Neuregulin 1 (NRG1) is a frequently identified schizophrenia susceptibility gene that has also been associated with the psychotic features of bipolar disorder. Previously, we established that Type II NRG1 is expressed in the hypothalamic-pituitary-adrenal (HPA) axis neurocircuitry. We also found, using a line of Nrg1 hypomorphic rats (Nrg1(Tn)), that genetic disruption of Type II NRG1 results in altered HPA axis function and environmental reactivity. The present studies used the Nrg1(Tn) rats to test whether Type II NRG1 gene disruption and chronic stress exposure during adolescence interact to alter adult anxiety- and fear-related behaviors. Male and female Nrg1(Tn) and wild-type rats were exposed to chronic variable stress (CVS) during mid-adolescence and then tested for anxiety-like behavior, cued fear conditioning and basal corticosterone secretion in adulthood. The disruption of Type II NRG1 alone significantly impacts rat anxiety-related behavior by reversing normal sex-related differences and impairs the ability to acquire cued fear conditioning. Sex-specific interactions between genotype and adolescent stress also were identified such that CVS-treated wild-type females exhibited a slight reduction in anxiety-like behavior and basal corticosterone, while CVS-treated Nrg1(Tn) females exhibited a significant increase in cued fear extinction. These studies confirm the importance of Type II NRG1 in anxiety and fear behaviors and point to adolescence as a time when stressful experiences can shape adult behavior and HPA axis function.

The digital revolution and adolescent brain evolution

Remarkable advances in technologies that enable the distribution and use of information encoded as digital sequences of 1s or 0s have dramatically changed our way of life. Adolescents, old enough to master the technologies and young enough to welcome their novelty, are at the forefront of this "digital revolution." Underlying the adolescent's eager embracement of these sweeping changes is a neurobiology forged by the fires of evolution to be extremely adept at adaptation. The consequences of the brain's adaptation to the demands and opportunities of the digital age have enormous implications for adolescent health professionals.

Executive dysfunction in pediatric posterior fossa tumor survivors: a systematic literature review of neurocognitive deficits and interventions

Improved medical therapies have increased survivorship rates for children with posterior fossa tumors; resultantly, morbidities associated with survivorship, such as executive function deficits, have become increasingly important to identify and address. Executive dysfunction can impact academic achievement as well as functional outcomes. We summarize studies describing executive functioning deficits in pediatric posterior fossa tumor survivors who received cranial radiation therapy and intervention studies that have targeted executive functioning deficits. Previous theoretical models describing the etiology of these deficits are reviewed, and a new, more comprehensive model is proposed. Future research should move toward incorporating neuroimaging, longitudinal designs, and multiple informants.

Adolescent brain development, substance use, and psychotherapeutic change

Adolescence is a unique developmental period characterized by major physiological, psychological, social, and brain changes, as well as an increased incidence of maladaptive, addictive behaviors. With the use of MRI techniques, researchers have been able to provide a better understanding of adolescent brain maturation and how neurodevelopment affects cognition and behavior. This review discusses adolescent brain development and its potential influence on psychotherapeutic change. We focus on cognitive-behavioral and mindfulness-based approaches for treating substance use and highlight potential brain mechanisms underlying response to psychotherapy. Finally, we discuss integrative neuroimaging and treatment studies and potential opportunities for advancing the treatment of adolescent addictive behaviors.

Peers increase adolescent risk taking by enhancing activity in the brain's reward circuitry

The presence of peers increases risk taking among adolescents but not adults. We posited that the presence of peers may promote adolescent risk taking by sensitizing brain regions associated with the anticipation of potential rewards. Using fMRI, we measured brain activity in adolescents, young adults, and adults as they made decisions in a simulated driving task. Participants completed one task block while alone, and one block while their performance was observed by peers in an adjacent room. During peer observation blocks, adolescents selectively demonstrated greater activation in reward-related brain regions, including the ventral striatum and orbitofrontal cortex, and activity in these regions predicted subsequent risk taking. Brain areas associated with cognitive control were less strongly recruited by adolescents than adults, but activity in the cognitive control system did not vary with social context. Results suggest that the presence of peers increases adolescent risk taking by heightening sensitivity to the potential reward value of risky decisions.

The mental and physical health of homeless youth: a literature review

Youth homelessness is a growing concern in the United States. Despite difficulties studying this population due to inconsistent definitions of what it means to be a youth and homeless, the current body of research indicates that abuse, family breakdown, and disruptive family relationships are common contributing factors to youth homelessness. Moreover, the experience of homelessness appears to have numerous adverse implications and to affect neurocognitive development and academics, as well as mental and physical health. Substance use, sexually transmitted infections, and psychiatric disorders are particularly prevalent in this population. Whereas some of these problems may be short-lived, the chronic stress and deprivation associated with homelessness may have long-term effects on development and functioning. Further, difficulties accessing adequate and developmentally-appropriate health care contribute to more serious health concerns. Suggestions for future research and interventions are discussed.

Neurocognitive alterations in hypertensive children and adolescents

Hypertensive adults demonstrate performance deficits on neuropsychological testing compared with scores of normotensive controls. This article reviews emerging preliminary evidence that children with hypertension also manifest neurocognitive differences when compared with normotensive controls. Database and single-center studies suggest that children with hypertension manifest deficits on measures of neurocognition and have an increased prevalence of learning difficulties and that children with hypertension associated with obesity may be at increased risk for depression and anxiety. Studies suggesting blunted cerebrovascular reactivity in children with hypertension are also reviewed.

Pre-schoolers suffering from psychiatric disorders show increased cortisol secretion and poor sleep compared to healthy controls

BACKGROUND

Various studies of child cortisol secretion and sleep show a close association between poor sleep, deterioration of the HPA axis and unfavorable psychological functioning. However, there is little evidence as to whether these associations are clearly present in pre-school children suffering from psychiatric disorders.

METHOD

A total of 30 pre-schoolers suffering from psychiatric disorders (anxiety, adjustment disorders, emotional and attachment disorder; hyperactivity or oppositional disorder) and 35 healthy controls took part in the study. Saliva cortisol secretion was assessed both at baseline and under challenge conditions. Sleep was assessed via activity monitoring for seven consecutive days and nights, using a digital movement-measuring instrument. Parents and teachers completed questionnaires assessing children's cognitive, emotional and social functioning. The Berkeley Puppet Interview provided child-based reports of cognitive-emotional processes.

RESULTS

Compared to healthy controls, children suffering from psychiatric disorders had much higher cortisol secretion both at baseline and under challenge conditions. Sleep was also more disturbed, and parents and teachers rated children suffering from psychiatric disorders as cognitively, emotionally and behaviorally more impaired, relative to healthy controls. Children with psychiatric disorders reported being more bullied and victimized.

CONCLUSIONS

In five-year old children the presence of psychiatric disorders is reflected not only at psychological, social and behavioral, but also at neuroendocrine and sleep-related levels. It is likely that these children remain at increased risk for suffering from psychiatric difficulties later in life.

Psychosocial Care of Adolescent and Young Adult Patients With Cancer and Survivors

The delivery of quality care for adolescent and young adult (AYA) patients with cancer and survivors requires an understanding of the unique qualities of this group—the shared norms, attitudes, and beliefs that determine their behavior as well as the unique stresses they face on a day-to-day basis. All AYAs have typical concerns about being comfortable with who they are and who they want to become (identity development, including sexual identity), their bodies (body image), initiating intimate and emotional relationships, separating from parents, and making independent decisions about future goals such as career, higher education, and/or family (autonomy). Yet efforts of AYA patients with cancer and survivors to mature are often confounded by restrictions and limitations placed on them by their disease and treatment. This article promotes understanding of psychosocial challenges faced by AYAs when diagnosed with and treated for cancer. It reviews evidence-based psychosocial support interventions for AYAs with cancer and other life-threatening or chronic diseases, particularly the positive effects of peer support, technology-based interventions, and skill-based interventions. The article concludes with recommendations for clinical care that are intended to promote the ability of AYAs to cope with cancer.

Unique relations of age and delinquency with cognitive control

Context processing has significant empirical support as an explanation of age- and psychopathology-related deficiencies in cognitive control. We examined whether context processing generalizes to younger individuals who are in trouble with the law. We tested whether age and delinquency might have unique relations to context processing skills in four samples of male participants: adolescent offenders (n = 43), control adolescents (n = 33), young adult offenders (n = 40), and control young adults (n = 31). We used a modified Stroop task to measure context processing (i.e., attention, memory, and response inhibition). Task performance was superior for older participants in conditions most demanding of context processing skills. Adolescent offenders and control adolescents showed difficulties engaging selective attention to filter out irrelevant information, even after controlling for the effects of age. Control adolescents made the most errors in the condition most demanding of context processing, whereas the other three samples showed slower processing but fewer errors in context processing.

Anhedonia predicts poorer recovery among youth with selective serotonin reuptake inhibitor treatment-resistant depression

OBJECTIVE

To identify symptom dimensions of depression that predict recovery among selective serotonin reuptake inhibitor (SSRI) treatment-resistant adolescents undergoing second-step treatment.

METHOD

The Treatment of Resistant Depression in Adolescents (TORDIA) trial included 334 SSRI treatment-resistant youth randomized to a medication switch, or a medication switch plus CBT. This study examined five established symptom dimensions (Child Depression Rating Scale-Revised) at baseline as they predicted recovery over 24 weeks of acute and continuation treatment. The two indices of recovery that were evaluated were time to remission and number of depression-free days.

RESULTS

Multivariate analyses examining all five depression symptom dimensions simultaneously indicated that anhedonia was the only dimension to predict a longer time to remission, and also the only dimension to predict fewer depression-free days. In addition, when anhedonia and CDRS-total score were evaluated simultaneously, anhedonia continued to uniquely predict longer time to remission and fewer depression-free days.

CONCLUSIONS

Anhedonia may represent an important negative prognostic indicator among treatment-resistant depressed adolescents. Further research is needed to elucidate neurobehavioral underpinnings of anhedonia, and to test treatments that target anhedonia in the context of overall treatment of depression.

Patterns of alcohol use and multiple risk behaviour by gender during early and late adolescence: the ALSPAC cohort

BACKGROUND

Adolescent risk behaviours such as smoking, alcohol use and antisocial behaviour are associated with increased risk of morbidity and mortality. Patterns of risk behaviour may vary between genders during adolescence.

METHODS

Analysis of data from a longitudinal birth cohort to assess the prevalence and distribution of multiple risk behaviours by gender at age 15-16 years with a focus on alcohol use at age 10, 13 and 15 years.

RESULTS

By age 15 years, over half of boys and girls had consumed alcohol and one-fifth had engaged in binge drinking with no clear difference by gender. At age 15-16 years, the most prevalent risk behaviours were physical inactivity (74%), antisocial and criminal behaviour (42%) and hazardous drinking (34%). Boys and girls engaged in a similar number of behaviours but antisocial and criminal behaviours, cannabis use and vehicle-related risk behaviours were more prevalent among boys, whilst tobacco smoking, self-harm and physical inactivity were more prevalent among girls.

CONCLUSION

Multiple risk behaviour is prevalent in both genders during adolescence but the pattern of individual risk behaviour varies between boys and girls. Effective interventions at the individual, family, school, community or population level are needed to address gender-specific patterns of risk behaviour during adolescence.

"Sexting" among U.S. adolescents: psychological and legal perspectives

This article will discuss the phenomenon of "sexting" (i.e., the exchange of sexually explicit images between adolescents via cell phone) in the United States, with a particular focus on clinical and legal implications. Although sexting is frequently discussed in the popular press, there is virtually no scientific literature available on this topic. In contrast, the legal literature has discussed sexting more comprehensively due to the implications of child pornography statutes for the social response to involved youth. This article will consider sexting from a clinical and legal perspective, and recommend ways to understand and address this practice clinically with adolescent patients.

Developmental aspects of sleep slow waves: linking sleep, brain maturation and behavior

Sleep slow waves are the major electrophysiological features of non-rapid eye movement (NREM) sleep. Although there is growing understanding of where slow waves originate and how they are generated during sleep, the function of slow waves is still largely unclear. A recently proposed hypothesis relates slow waves to the homeostatic regulation of synaptic plasticity. While several studies confirm a correlation between experimentally triggered synaptic changes and slow-wave activity (SWA), little is known about its association to synaptic changes occurring during cortical maturation. Interestingly, slow waves undergo remarkable changes during development that parallel the time course of cortical maturation. In a recent cross-sectional study including children and adolescents, the topographical distribution of SWA was analyzed with high-density electroencephalography. The results showed age-dependent differences in SWA topography: SWA was highest over posterior regions during early childhood and then shifted over central derivations to the frontal cortex in late adolescence. This trajectory of SWA topography matches the course of cortical gray maturation. In this chapter, the major changes in slow waves during development are highlighted and linked to cortical maturation and behavior. Interestingly, synaptic density and slow-wave amplitude increase during childhood are highest shortly before puberty, decline thereafter during adolescence, reaching overall stable levels during adulthood. The question arises whether SWA is merely reflecting cortical changes or if it plays an active role in brain maturation. We thereby propose a model, by which sleep slow waves may contribute to cortical maturation. We hypothesize that while there is a balance between synaptic strengthening and synaptic downscaling in adults, the balance of strengthening/formation and weakening/elimination is tilted during development.

Neuropsychological functioning in girls with premature adrenarche

Contemporary research indicates that brain development occurs during childhood and into early adulthood, particularly in certain regions. A critical question is whether premature or atypical hormone exposures impact brain development (e.g., structure) or function (e.g., neuropsychological functioning). The current study enrolled 40 girls (aged 6-8 years) diagnosed with premature adrenarche (PA) and a comparison group of 36 girls with on-time maturation. It was hypothesized that girls with PA would demonstrate lower IQ and performance on several neuropsychological tasks. The potential for a sexually dimorphic neuropsychological profile in PA was also explored. No significant univariate or multivariate group differences emerged for any neuropsychological instrument. However, effect size confidence intervals contained medium-sized group differences at the subscale level. On-time girls performed better on verbal, working memory, and visuospatial tasks. Girls with PA showed improved attention, but not a sexually dimorphic profile. These results, though preliminary, suggest that premature maturation may influence neuropsychological functioning.

Temperament, character, and adolescents' depressive symptoms: focusing on affect

Positive (PA) and negative affect (NA) are two separate systems markers of subjective well-being and measures of the state depression (low PA combined with high NA). The present study investigated differences in temperament, character, locus of control, and depressive symptoms (sleep quality, stress, and lack of energy) between affective profiles in an adolescent sample. Participants (N = 304) were categorized into four affective profiles: "self-fulfilling" (high PA, low NA), "high affective" (high PA, high NA), "low affective" (low PA, low NA), and "self-destructive" (low PA, high NA). Personality was measured by the Temperament and Character Inventory and affective profiles by the Positive Affect and Negative Affect Schedule. The "self-fulfilling" profile was characterized by, compared to the other affective profiles, higher levels of sleep quality, less stress and more energy and also higher levels of persistence and a mature character (i.e., high scores in self-directedness and cooperativeness). "Self-destructive" adolescents reported higher levels of external locus of control, high scores in harm avoidance and reward dependence combined with less mature character. The results identify the importance of character maturity in well-being and suggest that depressive state can be positively influenced by promoting positive emotions which appears to be achieved by character development.

Building better brains: evidence-based interventions to enhance contemporary schooling

School is a rich environment for cultivating academic skills, but also for developing metacognitive skills such as executive functioning and emotional regulation. However, the hours students spend in school are often guided by familiar practices rather than contemporary findings about how the brain best learns and grows. This article describes biological conditions favorable to brain development, psychological skills associated with effective school functioning, and school practices associated with academic and interpersonal success. The aim is that schooling might be shaped with regard to children’s and adolescents’ brain development needs rather than social custom.

Brain processes in discounting: consequences of adolescent methylphenidate exposure

Traits of inattention, impulsivity, and motor hyperactivity characterize children diagnosed with attention-deficit/hyperactivity disorder (ADHD), whose inhibitory control is reduced. In animal models, crucial developmental phases or experimental transgenic conditions account for peculiarities, such as sensation-seeking and risk-taking behaviors, and reproduce the beneficial effects of psychostimulants. An "impulsive" behavioral profile appears to emerge more extremely in rats when forebrain dopamine (DA) systems undergo remodeling, as in adolescence, or with experimental manipulation tapping onto the dopamine transporter (DAT). Ritalin(®) (methylphenidate, MPH), a DAT-blocking drug, is prescribed for ADHD therapy but is also widely abused by human adolescents. Administration of MPH during rats' adolescence causes a long-term modulation of their self-control, in terms of reduced intolerance to delay and diminished proneness for risk when reward is uncertain. Exactly the opposite profile emerges when exogenous alteration of DAT levels is achieved via lentiviral transfection. Both adolescent MPH exposure and DAT-targeting transfection lead to enduring hyperfunction of dorsal striatum and hypofunction of ventral striatum. Together with upregulation of prefronto-cortical phospho-creatine, striatal upregulation of selected genes (like serotonin 7 receptor gene) suggests that enhanced inhibitory control is generated by adolescent MPH exposure. Operant tasks, which assess the balance between motivational drives and inhibitory self-control, are thus useful for investigating reward-discounting processes and their modulation by DAT-targeting tools. In summary, due to the complexity of human studies, preclinical investigations of rodent models are necessary to understand better both the neurobiology of ADHD-like symptoms' etiology and the long-term therapeutic safety of adolescent MPH exposure.

Chronic ethanol exposure during adolescence alters the behavioral responsiveness to ethanol in adult mice

Alcohol exposure during early adolescence is believed to durably alter the behavioral properties of ethanol, increasing the likelihood of later alcohol-related disorders. The aim of the present experiments was to characterize changes in the behavioral effects of ethanol in adult female Swiss mice after a chronic ethanol exposure during adolescence, extending from postnatal day 28 to postnatal day 42. After a chronic ethanol exposure during adolescence (daily injections of 0, 2.5 or 4 g/kg ethanol for 14 consecutive days), adult mice were tested at postnatal day 63. The locomotor stimulant effects of ethanol, together with ethanol sensitization were tested in experiment 1. In experiment 2, the sedative effects of ethanol were assessed with the loss of righting reflex procedure. Finally, in experiment 3, the anxiolytic effects of ethanol were tested with the light/dark box test. Adult mice chronically exposed to ethanol during adolescence showed a lower basal locomotor activity, but higher locomotor stimulant effects of ethanol than non-exposed mice. Additionally, these adult mice developed higher rates of ethanol sensitization after chronic re-exposure to ethanol in adulthood. Adult mice exposed to ethanol during adolescence also had a stronger tolerance to the sedative effects of high ethanol doses, although they showed no evidence of changes in the anxiolytic effects of ethanol. These results are in agreement with the thesis that chronic alcohol consumption during adolescence, especially in high amounts, increases the risk of later alcohol-related disorders.

Age and sex effects levels of choline compounds in the anterior cingulate cortex of adolescent methamphetamine users

BACKGROUND

Methamphetamine can be neurotoxic to the adult brain; however, many individuals first use methamphetamine during adolescence, and the drug's impact on this period of brain development is unknown. Therefore, we evaluated young methamphetamine users for possible abnormalities in brain metabolite concentrations.

METHODS

Anterior cingulate cortex (ACC), frontal white matter (FWM), basal ganglia, and thalamus were studied with localized proton magnetic resonance spectroscopy in 54 periadolescent (ages 13-23 years) methamphetamine users and 53 comparison subjects. The concentrations of major brain metabolites and their associations with age, sex and cognition were assessed.

RESULTS

FWM total-creatine correlated with age in methamphetamine-using males and comparison females, but not comparison males or methamphetamine-using females, leading to a drug by sex by age interaction (p=0.003) and ACC choline-containing compounds (CHO) correlated with age only in comparison males leading to a drug by sex by age interaction (p=0.03). Higher ACC CHO was associated with faster performance on the Stroop Interference task in the control males. Male methamphetamine users had slowest performance on the Stroop Interference task and did not show age-appropriate levels of ACC CHO.

CONCLUSIONS

The altered age-appropriate levels of ACC CHO and poorer executive function in male methamphetamine users suggest methamphetamine abuse may interfere with brain maturation. These periadolescents did not have the abnormal neuronal markers previously reported in adult methamphetamine users, suggesting that neuronal abnormalities may be the result of long-term use or interference in normal cortical maturation, emphasizing the need for early intervention for young methamphetamine users.

Pediatric sports-related concussion

This article aims to examine pediatric concussion literature with respect to epidemiology, etiology, return to play, and recurrent concussions, and to provide recommendations for future research. We conducted a review of pediatric concussion literature regarding incidence, etiology, return to play, and recurrent concussive injury by using MEDLINE, CINAHL, Sport-Discus, and PsychInfo databases from 1995-2010. A review of reference lists in the aforementioned articles was also performed. We discovered that the research on sports-related concussion specific to children and adolescents is rather limited. Results of existing studies of concussion incidence in this population indicate that concussion is relatively rare compared with most musculoskeletal injuries; however, the potential consequences of mismanagement and of subsequent injury warrant significant attention regarding injury recognition and recovery, and the challenge of determining readiness to return to play. Evidence exists that children and adolescents take longer to recover than adults after a concussion, which underscores the need for a more conservative approach to management and return to physical and cognitive activities. Concussion in the young athlete is of specific concern because of the continuing cognitive maturation, therefore, the recovery may be more difficult to track when using the standard assessment tools currently available. Until future studies can better delineate the mechanisms of, response to, and recovery from concussion in the young athlete, it is prudent to act in a conservative manner when dealing with pediatric athletes with concussion.

Antidepressants and adolescent brain development

Despite being a first-line treatment for adolescent depression and anxiety, antidepressant drugs appear to have questionable efficacy and carry an increased risk of adverse effects in this population. The neural mechanisms underlying this phenomenon are currently unknown. Recent research into the neural effects of alcohol and recreational drugs suggests that the developmental trajectory of the adolescent brain may be particularly vulnerable to pharmacological disturbance. It is therefore important to consider whether prescription psychotropic drugs may have analogous effects. This article reviews the contribution of recent preclinical, clinical and pharmacogenetic literature to current knowledge on the short-term and enduring neural effects of antidepressants on the adolescent brain, with a particular focus on the major neurotransmitter systems and neuroplasticity.

The impact of age at transfer from pediatric to adult-oriented care on renal allograft survival

Immaturity among individuals transferred from pediatric to adult-oriented care at a young age may leave them vulnerable to higher graft failure risks than in individuals transferred older. We sought to determine the impact of age at transfer on renal allograft failure rates. We evaluated graft failure rates among 440 kidney recipients recorded in the UNOS database (1987-2007), who had been transferred from pediatric to adult care. Transfers were identified using the center codes recorded at yearly data collection. Failure rates for those transferred early (<21 yr old) were compared with rates for those transferred late (≥21 yr old); time-dependent Cox models were used to estimate the additional risk of graft failure associated with early vs. late transfer. The age-standardized failure rate was 12.9 per 100 person-years among those transferred early, and 8.7 per 100 person-years among those transferred late. Compared with individuals the same age who had transferred late, graft failure rates were 58% higher ([95% confidence interval: 7%, 134%], p = 0.02) among those who had transferred early. Younger age at transfer to adult care is associated with higher graft failure rates. Transfer to adult-oriented care at <21 yr of age should be undertaken with caution.

Molecular and behavioral aspects of the actions of alcohol on the adult and developing brain

The brain is one of the major target organs of alcohol actions. Alcohol abuse can lead to alterations in brain structure and functions and, in some cases, to neurodegeneration. Cognitive deficits and alcohol dependence are highly damaging consequences of alcohol abuse. Clinical and experimental studies have demonstrated that the developing brain is particularly vulnerable to alcohol, and that drinking during gestation can lead to a range of physical, learning and behavioral defects (fetal alcohol spectrum disorders), with the most dramatic presentation corresponding to fetal alcohol syndrome. Recent findings also indicate that adolescence is a stage of brain maturation and that heavy drinking at this stage can have a negative impact on brain structure and functions causing important short- and long-term cognitive and behavioral consequences. The effects of alcohol on the brain are not uniform; some brain areas or cell populations are more vulnerable than others. The prefrontal cortex, the hippocampus, the cerebellum, the white matter and glial cells are particularly susceptible to the effects of ethanol. The molecular actions of alcohol on the brain are complex and involve numerous mechanisms and signaling pathways. Some of the mechanisms involved are common for the adult brain and for the developing brain, while others depend on the developmental stage. During brain ontogeny, alcohol causes irreversible alterations to the brain structure. It also impairs several molecular, neurochemical and cellular events taking place during normal brain development, including alterations in both gene expression regulation and the molecules involved in cell-cell interactions, interference with the mitogenic and growth factor response, enhancement of free radical formation and derangements of glial cell functions. However, in both adult and adolescent brains, alcohol damages specific brain areas through mechanisms involving excitotoxicity, free radical formation and neuroinflammatory damage resulting from activation of the innate immune system mediated by TLR4 receptors. Alcohol also acts on specific membrane proteins, such as neurotransmitter receptors (e.g. NMDA, GABA-A), ion channels (e.g. L-type Ca²⁺ channels, GIRKs), and signaling pathways (e.g. PKA and PKC signaling). These effects might underlie the wide variety of behavioral effects induced by ethanol drinking. The neuroadaptive changes affecting neurotransmission systems which are more sensitive to the acute effects of alcohol occur after long-term alcohol consumption. Alcohol-induced maladaptations in the dopaminergic mesolimbic system, abnormal plastic changes in the reward-related brain areas and genetic and epigenetic factors may all contribute to alcohol reinforcement and alcohol addiction. This manuscript reviews the mechanisms by which ethanol impacts the adult and the developing brain, and causes both neural impairments and cognitive and behavioral dysfunctions. The identification and the understanding of the cellular and molecular mechanisms involved in ethanol toxicity might contribute to the development of treatments and/or therapeutic agents that could reduce or eliminate the deleterious effects of alcohol on the brain.