The teen brain: insights from neuroimaging

The influence of self-compassion on emotional well-being among early and older adolescent males and females

Self-compassion has been associated with well-being in adult samples, but has rarely been assessed in adolescents. In this study, 90 students ages 11-18 completed an online survey assessing self-compassion, life satisfaction, perceived stress and positive and negative affect. Findings indicated that older female adolescents had lower self-compassion than either older male adolescents or early adolescents of either gender, and self-compassion was associated significantly with all dimensions of emotional well-being with the exception of positive affect. Additionally, phase of adolescence, but not gender, was found to moderate the relationship between self-compassion and dimensions of well-being; for older adolescents, the inverse relationship between self-compassion and negative affect was stronger. Lastly, the influence of the various components of self-compassion was investigated and discussed.

Anhedonia and depressed mood in adolescence: course, stability, and reciprocal relation in the TRAILS study

Adolescence is marked by increases in the incidence of major depression (MDD), a disorder recognized as one of the leading causes of disability. Anhedonia and depressed mood predict both onset and chronicity of major depression (MDD), but have never been studied together longitudinally in the general adolescent population. The present study examined (1) the course and the stability of anhedonia and depressed mood and (2) their cross-sectional and longitudinal relations during adolescence. The study cohort consisted of 2,230 adolescents. Anhedonia and depressed mood were assessed with items of the YSR and ASR self-report forms at four measurement waves between ages 11 and 19. The proportion of adolescents reporting anhedonia decreased between ages 11 and 19, while the proportion of female adolescents reporting depressed mood increased. The stability of anhedonia and the cross-sectional association between anhedonia and depressed mood was larger at age 19 than at age 11. We found a mutual association between anhedonia and depressed mood without a clear temporal sequence. The presence of anhedonia at the end of adolescence might put adolescents at increased risk for MDD given the increasingly stronger stability and association with depressed mood. This suggests that it becomes more difficult to prevent MDD during late adolescence compared with early and middle adolescence.

White matter integrity pre- and post marijuana and alcohol initiation in adolescence

Characterizing the effects of alcohol and marijuana use on adolescent brain development is important for understanding potential alterations in neurodevelopment. Several cross sectional studies have identified group differences in white matter integrity after initiation of heavy alcohol and marijuana use, however none have explored white matter trajectories in adolescents pre- and post initiation of use, particularly for marijuana users. This study followed 16 adolescents with minimal alcohol and marijuana use at ages 16–18 over three years. At follow-up, teens were 19–22 years old; half of the participants initiated heavy alcohol use and half initiated heavy alcohol and marijuana use. Repeated-measures ANOVA revealed 20 clusters in association and projection fibers tracts (p < 0.01) in which a group by time interaction was found. Most consistently, white matter integrity (i.e., fractional anisotropy) decreased for those who initiated both heavy alcohol and marijuana use over the follow-up interval. No effect of time or change in white matter integrity was seen for those who initiated alcohol use only in the majority of clusters. In most regions, at the baseline time point, teens who would later initiate both alcohol and marijuana use demonstrated white matter integrity greater than or equal to teens that initiated alcohol use only. Findings suggest poorer tissue integrity associated with combined initiation of heavy alcohol and marijuana use in late adolescence. While pre-existing differences may also be related to likelihood of substance use, the present data suggest an effect on tissue integrity for these teens transitioning to combined alcohol and marijuana use in later adolescence.

Associations between fractional anisotropy and problematic alcohol use in juvenile justice-involved adolescents

BACKGROUND

Studies have shown associations between heavy alcohol use and white matter alterations in adolescence. Youth involved with the juvenile justice system engage in high levels of risk behavior generally and alcohol use in particular as compared to their non-justice-involved peers.

OBJECTIVES

This study explored white matter integrity among justice-involved adolescents. Analyses examined fractional anisotropy (FA) and mean diffusivity (MD) between adolescents with low and high levels of problematic alcohol use as assessed by the Alcohol Use Disorders Identification Test (AUDIT).

METHODS

Participants (N = 125; 80% male; 14-18 years) completed measures assessing psychological status and substance use followed by diffusion tensor imaging (DTI). DTI data for low (n = 51) and high AUDIT (n = 74) adolescents were subjected to cluster-based group comparisons on skeletonized FA and MD data.

RESULTS

Whole-brain analyses revealed significantly lower FA in clusters in the right and left posterior corona radiata (PCR) and right superior longitudinal fasciculus (SLF) in the high AUDIT group, as well as one cluster in the right anterior corona radiata that showed higher FA in the high AUDIT group. No differences in MD were identified. Exploratory analyses correlated cluster FA with measures of additional risk factors. FA in the right SLF and left PCR was negatively associated with impulsivity.

CONCLUSION

Justice-involved adolescents with alcohol use problems generally showed poorer FA than their low problematic alcohol use peers. Future research should aim to better understand the nature of the relationship between white matter development and alcohol use specifically as well as risk behavior more generally.

Does future-oriented thinking predict adolescent decision making?

A number of theorists, as well as plain common sense, suggest that future-oriented thinking (FOT) should be involved in decision making; therefore, the development of FOT should be related to better quality decision making. FOT and quality of the decision making were measured in adolescents as well as adults in 2 different experiments. Though the results of the first experiment revealed an increase in quality of decision making across adolescence into adulthood, there was no relationship between FOT and decision making. In the second experiment, FOT predicted performance on a more deliberative decision-making task independent of age, but not performance on the Iowa Gambling Task (IGT). Performance on the IGT was instead related to emotion regulation. The study's findings suggest that FOT can be related to reflective decision making but not necessarily decision making that is more intuitive.

Impulsivity moderates the association between physical activity and alcohol consumption

Mounting evidence indicates that physical activity and alcohol consumption are positively associated, but potential moderators of this relationship remain unclear. Both physical activity and alcohol drinking are potentially reinforcing and may be more strongly associated among individuals who tend to be higher in reward seeking and related processes governed by the prefrontal cortex. Thus, behaviors linked to the prefrontal cortex, such as impulsivity, may influence the association between physical activity and alcohol intake. The present study therefore evaluated dimensions of impulsivity as moderators of the association between physical activity and alcohol consumption. We surveyed 198 undergraduate students and obtained self-reports of their drinking habits, physical activity, and dimensions of impulsivity. We found that moderate but not vigorous physical activity was positively associated with drinking. Linear regression analyses were used to evaluate dimensions of impulsivity as moderators of the association between physical activity (vigorous or moderate) and drinks per week. Results revealed a consistent pattern of interactions between the positive urgency and sensation seeking dimensions of impulsivity and moderate physical activity on number of drinks per week. For both interactions, there was a significant positive association between moderate physical activity and drinking at higher but not lower levels of impulsivity. We conclude that impulsivity moderates the positive association between physical activity and alcohol consumption. These results have significant implications for the development of prevention and treatment programs for alcohol use disorders.

Psychosocial barriers and facilitators to clinical trial enrollment and adherence for adolescents with cancer

Adolescents (aged 15-19 years) have not experienced the same survival gains as children and older adults diagnosed with cancer. Poor clinical trial enrollment and adherence rates among adolescents may account for some of this disparity. Although biological, regulatory, systemic, and practice-related challenges to clinical trial enrollment and adherence have been examined, studies of psychosocial factors, which can serve as barriers or facilitators to enrollment and adherence, are limited. To bring attention to these psychological factors, we reviewed existing literature on psychosocial barriers and facilitators that can affect an adolescent's decision to enroll and adhere to a clinical trial. We also provide potential strategies to address psychosocial factors affecting clinical trial accrual and adherence.

Trait rumination, depression, and executive functions in early adolescence

Although deficits in executive functions have been linked with both depression and rumination in adulthood, the nature of the relationship between these constructs is not well understood and remains understudied in adolescence. The present study examined the relationship of rumination and depression to deficits in executive functions in early adolescence, a critical developmental period for the emergence of depression and rumination and the development of executive functions. Participants were 486 early adolescents (52.7% female; 47.1% African American, 48.8% Caucasian; 4.2% Biracial/Multiracial/Other; M age = 12.88 years; SD = .62) and their mothers, recruited through local schools. Measures included (a) a semi-structured diagnostic interview of the mother and adolescent, (b) youth self-report forms assessing depressive symptoms and trait rumination, (c) mother-report forms assessing demographic information, and (d) behavioral tests of executive function (sustained, selective and divided attention, attentional set shifting, and working memory). Gender moderated rumination-set shifting associations, such that rumination predicted better set shifting in boys only. The current level of depressive symptoms moderated rumination-sustained attention associations, such that rumination predicted better sustained attention in those with low levels of depressive symptoms and worse sustained attention in those with high levels of depressive symptoms. Rumination did not predict performance on other measures of executive functions. Likewise, depressive symptoms and diagnosis were not associated with executive functions. Implications for future research are discussed.

Decreases in energy and increases in phase locking of event-related oscillations to auditory stimuli occur during adolescence in human and rodent brain

Synchrony of phase (phase locking) of event-related oscillations (EROs) within and between different brain areas has been suggested to reflect communication exchange between neural networks and as such may be a sensitive and translational measure of changes in brain remodeling that occur during adolescence. This study sought to investigate developmental changes in EROs using a similar auditory event-related potential (ERP) paradigm in both rats and humans. Energy and phase variability of EROs collected from 38 young adult men (aged 18-25 years), 33 periadolescent boys (aged 10-14 years), 15 male periadolescent rats [at postnatal day (PD) 36] and 19 male adult rats (at PD103) were investigated. Three channels of ERP data (frontal cortex, central cortex and parietal cortex) were collected from the humans using an 'oddball plus noise' paradigm that was presented under passive (no behavioral response required) conditions in the periadolescents and under active conditions (where each subject was instructed to depress a counter each time he detected an infrequent target tone) in adults and adolescents. ERPs were recorded in rats using only the passive paradigm. In order to compare the tasks used in rats to those used in humans, we first studied whether three ERO measures [energy, phase locking index (PLI) within an electrode site and phase difference locking index (PDLI) between different electrode sites] differentiated the 'active' from 'passive' ERP tasks. Secondly, we explored our main question of whether the three ERO measures differentiated adults from periadolescents in a similar manner in both humans and rats. No significant changes were found in measures of ERO energy between the active and passive tasks in the periadolescent human participants. There was a smaller but significant increase in PLI but not PDLI as a function of active task requirements. Developmental differences were found in energy, PLI and PDLI values between the periadolescents and adults in both the rats and the human participants. Neuronal synchrony as indexed by PLI and PDLI was significantly higher to the infrequent (target) tone compared to the frequent (nontarget) tone in all brain sites in all of the regions of interest time-frequency intervals. Significantly higher ERO energy and significantly lower synchrony was seen in the periadolescent humans and rats compared to their adult counterparts. Taken together these findings are consistent with the hypothesis that adolescent remodeling of the brain includes decreases in energy and increases in synchrony over a wide frequency range both within and between neuronal networks and that these effects are conserved over evolution.

Sorting Test, Tower Test, and BRIEF-SR do not predict school performance of healthy adolescents in preuniversity education

Executive functions (EF) such as self-monitoring, planning, and organizing are known to develop through childhood and adolescence. They are of potential importance for learning and school performance. Earlier research into the relation between EF and school performance did not provide clear results possibly because confounding factors such as educational track, boy-girl differences, and parental education were not taken into account. The present study therefore investigated the relation between executive function tests and school performance in a highly controlled sample of 173 healthy adolescents aged 12-18. Only students in the pre-university educational track were used and the performance of boys was compared to that of girls. Results showed that there was no relation between the report marks obtained and the performance on executive function tests, notably the Sorting Test and the Tower Test of the Delis-Kaplan Executive Functions System (D-KEFS). Likewise, no relation was found between the report marks and the scores on the Behavior Rating Inventory of Executive Function-Self-Report Version (BRIEF-SR) after these were controlled for grade, sex, and level of parental education. The findings indicate that executive functioning as measured with widely used instruments such as the BRIEF-SR does not predict school performance of adolescents in preuniversity education any better than a student's grade, sex, and level of parental education.

Functional imaging of an alcohol-Implicit Association Test (IAT)

This research assessed activation in neural substrates involved in implicit associative processes through functional magnetic resonance imaging of an alcohol-Implicit Association Test (IAT) focused on positive outcomes of alcohol use. Comparisons involved 17 heavy and 19 light drinkers, ranging in age from 18 to 22, during compatible and incompatible association task trials. Behaviorally, a significant IAT effect was found with heavy drinkers showing stronger positive implicit associations toward alcohol use than light drinkers. Imaging data revealed heavy drinkers showed greater activity during compatible trials relative to incompatible trials in the left putamen and insula while no significant difference in activity between conditions was found in the light drinkers. Light drinkers showed significantly more activity in the left orbital frontal cortex during both compatible and incompatible trials than heavy drinkers, and the dorsolateral prefrontal cortex was engaged more in both light and heavy drinkers during incompatible trials relative to compatible trials. Further, within-group analyses showed significant amygdala activity along with the putamen and insula among heavy drinkers during compatible trials relative to incompatible trials. These results are consistent with a dual process framework of appetitive behaviors proposing that (1) implicit associations underlying habit are mediated through neural circuitry dependent on the striatum, and (2) controlled behaviors are mediated through neural circuitry more dependent on the prefrontal cortex. This is the first study to evaluate the neural mechanisms elicited by an alcohol-IAT, providing an additional step toward increasing understanding of associative habit processes and their regulatory influence over addictive behaviors.

Adolescence, attention allocation, and driving safety

Motor vehicle crashes are the leading source of morbidity and mortality in adolescents in the United States and the developed world. Inadequate allocation of attention to the driving task and to driving hazards are important sources of adolescent crashes. We review major explanations for these attention failures with particular focus on the roles that brain immaturity and lack of driving experience play in causing attention problems. The review suggests that the potential for overcoming inexperience and immaturity with training to improve attention to both the driving task and hazards is substantial. Nevertheless, there are large individual differences in both attentional abilities and risky driving tendencies that pose challenges to novice driver policies. Research that can provide evidence-based direction for such policies is urgently needed.

Gaining insight into adolescent vulnerability for social anxiety from developmental cognitive neuroscience

Social anxiety disorder (SAD) markedly impairs daily functioning. For adolescents, SAD can constrain typical development precisely when social experiences broaden, peers' opinions are highly salient, and social approval is actively sought. Individuals with extreme, impairing social anxiety fear evaluation from others, avoid social interactions, and interpret ambiguous social cues as threatening. Yet some degree of social anxiety can be normative and non-impairing. Furthermore, a temperament of behavioral inhibition increases risk for SAD for some, but not all adolescents with this temperament. One fruitful approach taken to understand the mechanisms of social anxiety has been to use neuroimaging to link affect and cognition with neural networks implicated in the neurodevelopmental social reorientation of adolescence. Although initial neuroimaging studies of adolescent SAD and risk for SAD underscored the role of fear-processing circuits (e.g., the amygdala and ventral prefrontal cortex), recent work has expanded these circuits to include reward-processing structures in the basal ganglia. A growing focus on reward-related neural circuitry holds promise for innovative translational research needed to differentiate impairing from normative social anxiety and for novel ways to treat adolescent SAD that focus on both social avoidance and social approach.

Electroencephalogram coherence in children with and without autism spectrum disorders: decreased interhemispheric connectivity in autism

Electroencephalogram coherence was measured in children with autism spectrum disorders (ASD) and control children at baseline and while watching videos of a familiar and unfamiliar person reading a story. Coherence was measured between the left and right hemispheres of the frontal, parietal, and temporal-parietal lobes (interhemispheric) and between the frontal and parietal lobes in each hemisphere (intrahemispheric). A data-reduction technique was employed to identify the frequency (alpha) that yielded significant differences in video conditions. Children with ASD displayed reduced coherence at the alpha frequency between the left and right temporal-parietal lobes in all conditions and reduced coherence at the alpha frequency between left and right frontal lobes during baseline. No group differences in intrahemispheric coherence at the alpha frequency emerged at the chosen statistical threshold. Results suggest decreased interhemispheric connectivity in frontal and temporal-parietal regions in children with ASD compared to controls.

GABAergic contributions to alcohol responsivity during adolescence: insights from preclinical and clinical studies

There is a considerable body of literature demonstrating that adolescence is a unique age period, which includes rapid and dramatic maturation of behavioral, cognitive, hormonal and neurobiological systems. Most notably, adolescence is also a period of unique responsiveness to alcohol effects, with both hyposensitivity and hypersensitivity observed to the various effects of alcohol. Multiple neurotransmitter systems are undergoing fine-tuning during this critical period of brain development, including those that contribute to the rewarding effects of drugs of abuse. The role of developmental maturation of the γ-amino-butyric acid (GABA) system, however, has received less attention in contributing to age-specific alcohol sensitivities. This review integrates GABA findings from human magnetic resonance spectroscopy studies as they may translate to understanding adolescent-specific responsiveness to alcohol effects. Better understanding of the vulnerability of the GABA system both during adolescent development, and in psychiatric conditions that include alcohol dependence, could point to a putative mechanism, boosting brain GABA, that may have increased effectiveness for treating alcohol use disorders.

National Athletic Trainers' Association position statement: management of sport concussion

OBJECTIVE

To provide athletic trainers, physicians, and other health care professionals with best-practice guidelines for the management of sport-related concussions.

BACKGROUND

An estimated 3.8 million concussions occur each year in the United States as a result of sport and physical activity. Athletic trainers are commonly the first medical providers available onsite to identify and evaluate these injuries.

RECOMMENDATIONS

The recommendations for concussion management provided here are based on the most current research and divided into sections on education and prevention, documentation and legal aspects, evaluation and return to play, and other considerations.

Hippocampal volumes in juvenile neuronal ceroid lipofuscinosis: a longitudinal magnetic resonance imaging study

BACKGROUND

Juvenile neuronal ceroid lipofuscinosis is an inherited, autosomal recessive, progressive, neurodegenerative disorder of childhood. It belongs to the lysosomal storage diseases, which manifest with loss of vision, seizures, and loss of cognitive and motor functions, and lead to premature death. Imaging studies have shown cerebral and cerebellar atrophy, yet no previous studies evaluating particularly hippocampal atrophy have been published. This study evaluates the hippocampal volumes in adolescent juvenile neuronal ceroid lipofuscinosis patients in a controlled 5-year follow-up magnetic resonance imaging study.

METHODS

Hippocampal volumes of eight patients (three female, five male) and 10 healthy age- and sex-matched control subjects were measured from two repeated magnetic resonance imaging examinations. Three male patients did not have controls and were excluded from the statistics. In the patient group, the first examination was performed at the mean age of 12.2 years and the second examination at the mean age of 17.3 years. In the control group, the mean ages at the time of examinations were 12.5 years and 19.3 years.

RESULTS

Progressive hippocampal atrophy was found in the patient group. The mean total hippocampal volume decreased by 0.85 cm³ during the 5-year follow-up in the patient group, which corresponds to a 3.3% annual rate of volume loss. The whole brain volume decreased by 2.9% per year. The observed annual rate of hippocampal atrophy also exceeded the previously reported 2.4% annual loss of total gray matter volume in juvenile neuronal ceroid lipofuscinosis patients.

CONCLUSIONS

These data suggest that progressive hippocampal atrophy is one of the characteristic features of brain atrophy in juvenile neuronal ceroid lipofuscinosis in adolescence.

Updates in paediatric psycho-oncology

Childhood cancer accounts for less than 2% of all cancers diagnosed each year. About 12-14,000 children will be diagnosed in a given year with any type of cancer. Over the past fifty years, treatments and cure rates have improved from 10-20% five-year survival rates to between 80-85% five-year survival rates. Psychosocial support of children with cancer and their families has grown and has been more fully integrated into paediatric care over the past five decades. Increasing acceptance of the importance of addressing mental health has led to oncologists referring patients to specific resources and services. This paper provides updated information on psychosocial issues for those who treat children and adolescents with cancer and focuses on unique challenges for the paediatric psycho-oncologist. PubMed and PsycINFO databases were searched from January 2000 through June 2013 using key words: pediatrics, oncology, psychosocial care, family, siblings, cancer, psycho-oncology, psychosocial issues, depression, anxiety, survivorship, and end of life.

White matter characterization of adolescent binge drinking with and without co-occurring marijuana use: a 3-year investigation

The aims of this study were to investigate the consequences of prolonged patterns of alcohol and marijuana use on white matter integrity and neurocognitive functioning in late adolescence, and examine neurodevelopmental trajectories over three years of regular follow-up visits. Three groups of demographically similar teens received assessments every 1.5 years (controls with consistently minimal substance use, n=16; teens who gradually increase their heavy episodic drinking n=17, and continuous binge drinkers with heavy marijuana use, n=21), including comprehensive neuropsychological evaluations, diffusion tensor imaging, and detailed substance use interviews. One-way ANOVA identified fifteen white matter clusters that significantly differed between groups at 3-year follow-up, ages 19-22; controls consistently demonstrated higher values of tissue integrity across fiber tracts. Repeated measures ANOVA revealed significant declines in white matter integrity from baseline to 3-year follow-up in the subsample of substance users, along with poorer global neurocognitive performance in alcohol users with heavy marijuana use by the 18-month follow-up. Findings suggest healthier brain white matter microstructure and better neurocognitive performance for teens free from heavy alcohol and marijuana use. Long-term engagement in these substances may adversely influence white matter and increase vulnerability for development of neuropathology purported to underlie future risk-taking and addictive behaviors.

Prefrontal structural correlates of cognitive control during adolescent development: a 4-year longitudinal study

Maturation of cognitive control abilities has been attributed to the protracted structural maturation of underlying neural correlates during adolescence. This study examined the relationship between development of two forms of cognitive control (proactive and reactive control) and structural maturation of the ACC, dorsolateral pFC, and ventrolateral pFC (vlPFC) between early and mid adolescence using a longitudinal design. Adolescents (n = 92) underwent baseline assessments when they were 12 years old and follow-up assessments approximately 4 years later. At each assessment, structural MRI scans were acquired, and a modified Stroop task was performed. Results showed longitudinal improvements in reactive control between early and mid adolescence. Furthermore, magnitude of the improvement in proactive control was associated with reduced thinning of the right vlPFC across the sample, whereas the magnitude of the improvements in reactive control was associated with reduced thinning of the left ACC in men alone. These findings suggest that individual differences in the maturation of ACC and vlPFC underlie the development of two distinct forms of cognitive control between early and mid adolescence as well as highlight sex differences in this relationship.

Preferential detachment during human brain development: age- and sex-specific structural connectivity in diffusion tensor imaging (DTI) data

Human brain maturation is characterized by the prolonged development of structural and functional properties of large-scale networks that extends into adulthood. However, it is not clearly understood which features change and which remain stable over time. Here, we examined structural connectivity based on diffusion tensor imaging (DTI) in 121 participants between 4 and 40 years of age. DTI data were analyzed for small-world parameters, modularity, and the number of fiber tracts at the level of streamlines. First, our findings showed that the number of fiber tracts, small-world topology, and modular organization remained largely stable despite a substantial overall decrease in the number of streamlines with age. Second, this decrease mainly affected fiber tracts that had a large number of streamlines, were short, within modules and within hemispheres; such connections were affected significantly more often than would be expected given their number of occurrences in the network. Third, streamline loss occurred earlier in females than in males. In summary, our findings suggest that core properties of structural brain connectivity, such as the small-world and modular organization, remain stable during brain maturation by focusing streamline loss to specific types of fiber tracts.

Network efficiency in autism spectrum disorder and its relation to brain overgrowth

A substantial body of evidence links differences in brain size to differences in brain organization. We have hypothesized that the developmental aspect of this relation plays a role in autism spectrum disorder (ASD), a neurodevelopmental disorder which involves abnormalities in brain growth. Children with ASD have abnormally large brains by the second year of life, and for several years thereafter their brain size can be multiple standard deviations above the norm. The greater conduction delays and cellular costs presumably associated with the longer long-distance connections in these larger brains is thought to influence developmental processes, giving rise to an altered brain organization with less communication between spatially distant regions. This has been supported by computational models and by findings linking greater intra-cranial volume, an index of maximum brain-size during development, to reduced inter-hemispheric connectivity in individuals with ASD. In this paper, we further assess this hypothesis via a whole-brain analysis of network efficiency. We utilize diffusion tractography to estimate the strength and length of the connections between all pairs of cortical regions. We compute the efficiency of communication between each network node and all others, and within local neighborhoods; we then assess the relation of these measures to intra-cranial volume, and the differences in these measures between adults with autism and typical controls. Intra-cranial volume is shown to be inversely related to efficiency for wide-spread regions of cortex. Moreover, the spatial patterns of reductions in efficiency in autism bear a striking resemblance to the regional relationships between efficiency and intra-cranial volume, particularly for local efficiency. The results thus provide further support for the hypothesized link between brain overgrowth in children with autism and the efficiency of the organization of the brain in adults with autism.

Juvenile ethanol exposure increases rewarding properties of cocaine and morphine in adult DBA/2J mice

Convergent data showed that ethanol exposure during adolescence can alter durably ethanol-related behaviour at adulthood. However, the consequences of juvenile ethanol exposure on the reinforcing effects of other drugs of abuse remain unclear. In the present work, we evaluated in adult male DBA/2J mice the effects of early ethanol exposure on the sensitivity to the incentive effects of cocaine and morphine, and on extracellular signal-regulated kinase (ERK) activation in response to cocaine. Juvenile male mice received intragastric administration of ethanol (2×2.5g/kg/day) or water for 5 days starting on postnatal day 28. When reaching adult age (10 week-old), animals were subjected to an unbiased procedure to assess conditioned place preference (CPP) to cocaine or morphine. In addition, activation of ERK in response to an acute injection of cocaine was investigated using immunoblotting in the striatum and the nucleus accumbens. Mice that have been subjected to early ethanol exposure developed CPP to doses of cocaine (5mg/kg) or morphine (10mg/kg) below the threshold doses to induce CPP in water pre-exposed mice. In addition, early ethanol administration significantly increased striatal ERK phosphorylation normally induced by acute cocaine (10 and 20mg/kg) in adult mice. These results show that, in DBA/2J mice, early exposure to ethanol enhanced the perception of the incentive effects of cocaine and morphine. Ethanol pre-exposure also induced a positive modulation of striatal ERK signalling, in line with the inference that juvenile ethanol intake may contribute to the development of addictive behaviour at adult age.

Union status and sexual risk behavior among men in their 30s

CONTEXT

Understanding the relationship between union status and men's sexual risk behavior in their 30s is important to ensure appropriate reproductive health services for men in middle adulthood.

METHODS

Data from 1,083 men aged 34-41 who participated in the 2008-2010 wave of the National Survey of Adolescent Males were used to examine differentials in sexual risk behaviors by union status, past risk behavior and selected characteristics. Bivariate tabulations were done to assess relationships between current risk behavior and background variables, multinomial regression analysis was conducted to identify associations between union status and past risk behavior, and logistic regression analysis was used to assess associations between current behavior and both union status and past behavior.

RESULTS

Eight percent of men in their 30s had had three or more sexual partners in the last 12 months, 10% had had at least one risky partner and 8% had had concurrent partners. Men living outside co-residential unions reported higher levels of these behaviors (24%, 29% and 24%, respectively) than did married men (1-2%) or cohabiting men (7-12%). In multivariate analyses that controlled for past risk behavior, married men were less likely than cohabiting men to have had at least one risky partner or concurrent partners in the last year (odds ratio, 0.2 for each), while men who were not in a co-residential union had an increased likelihood of reporting each risk behavior (2.2-5.3).

CONCLUSIONS

Men in their 30s, especially those who are not married, engage in risky sexual behaviors. Further studies are needed to assess what contributes to behavioral differences by union status and what types of services might help men in this age-group reduce their risk.

Controversies about the enhanced vulnerability of the adolescent brain to develop addiction

Adolescence, defined as a transition phase toward autonomy and independence, is a natural time of learning and adjustment, particularly in the setting of long-term goals and personal aspirations. It also is a period of heightened sensation seeking, including risk taking and reckless behaviors, which is a major cause of morbidity and mortality among teenagers. Recent observations suggest that a relative immaturity in frontal cortical neural systems may underlie the adolescent propensity for uninhibited risk taking and hazardous behaviors. However, converging preclinical and clinical studies do not support a simple model of frontal cortical immaturity, and there is substantial evidence that adolescents engage in dangerous activities, including drug abuse, despite knowing and understanding the risks involved. Therefore, a current consensus considers that much brain development during adolescence occurs in brain regions and systems that are critically involved in the perception and evaluation of risk and reward, leading to important changes in social and affective processing. Hence, rather than naive, immature and vulnerable, the adolescent brain, particularly the prefrontal cortex, should be considered as prewired for expecting novel experiences. In this perspective, thrill seeking may not represent a danger but rather a window of opportunities permitting the development of cognitive control through multiple experiences. However, if the maturation of brain systems implicated in self-regulation is contextually dependent, it is important to understand which experiences matter most. In particular, it is essential to unveil the underpinning mechanisms by which recurrent adverse episodes of stress or unrestricted access to drugs can shape the adolescent brain and potentially trigger life-long maladaptive responses.

The effect of breakfast cereal consumption on adolescents' cognitive performance and mood

The aim of the current study was to investigate the effect of breakfast consumption on cognitive performance and mood in adolescents, and any interaction that breakfast consumption might have with cognitive load. The rationale for this approach was that the beneficial effects of any intervention with regard to cognitive function may be more readily apparent when more demands are placed on the system. Furthermore, as skipping breakfast is particularly prevalent within this age group, thus, we focused on adolescents who habitually skip breakfast. Cognitive load was modulated by varying the level of difficulty of a series of cognitive tasks tapping memory, attention, and executive functions. Mood measured with Bond–Lader scales (1974) as well as measures of thirst, hunger, and satiety were recorded at each test session both at baseline and after the completion of each test battery. Forty adolescents (mean age = 14:2) participated in this within-subjects design study. According to treatment, all participants were tested before and after the intake of a low Glycaemic index breakfast (i.e., a 35 g portion of AllBran and 125 ml semi-skimmed milk) and before and after no breakfast consumption. Assessment time had two levels: 8.00 am (baseline) and 10.45 am. The orders of cognitive load tasks were counterbalanced. Overall it appeared that following breakfast participants felt more alert, satiated, and content. Following breakfast consumption, there was evidence for improved cognitive performance across the school morning compared to breakfast omission in some tasks (e.g., Hard Word Recall, Serial 3's and Serial 7's). However, whilst participants performance on the hard version of each cognitive task was significantly poorer compared to the corresponding easy version, there was limited evidence to support the hypothesis that the effect of breakfast was greater in the more demanding versions of the tasks.

Neuroimmune activation and myelin changes in adolescent rats exposed to high-dose alcohol and associated cognitive dysfunction: a review with reference to human adolescent drinking

AIMS

The aim of the study was to assess whether intermittent ethanol administration to adolescent rats activates innate immune response and TLRs signalling causing myelin disruption and long-term cognitive and behavioural deficits.

METHODS

We used a rat model of intermittent binge-like ethanol exposure during adolescence.

RESULTS

Binge-like ethanol administration to adolescent rats increased the gene expression of TLR4 and TLR2 in the prefrontal cortex (PFC), as well as inflammatory cytokines TNFα and IL-1β. Up-regulation of TLRs and inflammatory mediators were linked with alterations in the levels of several myelin proteins in the PFC of adolescent rats. These events were associated with previously reported long-term cognitive dysfunctions. Conversely, the same ethanol treatment did not cause significant changes in either inflammatory mediators or myelin changes in the brain of adult rats.

CONCLUSION

Activation of innate immune receptors TLRs in the PFC appears to be involved in the neuroinflammation and demyelination processes induced by ethanol exposure during adolescence. The findings support the vulnerability of the juvenile brain to the effects of ethanol and the long-term cognitive consequences of binge drinking. In addition, ethanol-induced PFC dysfunctions might underlie the propensity of adolescents for impulsivity and to ignore the negative consequences of their behaviour, both of which could increase the risk of substance abuse.

Effects of anonymous peer observation on adolescents' preference for immediate rewards

Research suggests that the presence of peers influences adolescent risk-taking by increasing the perceived reward value of risky decisions. While prior work has involved observation of participants by their friends, the current study examined whether observation by an anonymous peer could elicit similarly increased reward sensitivity. Late adolescent participants completed a delay discounting task either alone or under the belief that performance was being observed from a neighboring room by an unknown viewer of the same gender and age. Even in this limited social context, participants demonstrated a significantly increased preference for smaller, immediate rewards when they believed that they were being watched. This outcome challenges several intuitive accounts of the peer effect on adolescent risk-taking, and indicates that the peer influence on reward sensitivity during late adolescence is not dependent on familiarity with the observer. The findings have both theoretical and practical implications for our understanding of social influences on adolescents' risky behavior.

New understanding of adolescent brain development: relevance to transitional healthcare for young people with long term conditions

Whether or not adolescence should be treated as a special period, there is now no doubt that the brain changes much during adolescence. From an evolutionary perspective, the idea of an under developed brain which is not fit for purpose until adulthood is illogical. Rather, the adolescent brain is likely to support the challenges specific to that period of life. New imaging techniques show striking changes in white and grey matter between 11 and 25 years of age, with increased connectivity between brain regions, and increased dopaminergic activity in the pre-frontal cortices, striatum and limbic system and the pathways linking them. The brain is dynamic, with some areas developing faster and becoming more dominant until other areas catch up. Plausible mechanisms link these changes to cognitive and behavioural features of adolescence. The changing brain may lead to abrupt behavioural change with attendant risks, but such a brain is flexible and can respond quickly and imaginatively. Society allows adolescent exuberance and creativity to be bounded and explored in relative safety. In healthcare settings these changes are especially relevant to young people with long term conditions as they move to young adult life; such young people need to learn to manage their health conditions with the support of their healthcare providers.

Sleep patterns and psychological functioning in families in northeastern Iran; evidence for similarities between adolescent children and their parents

Sleep and well-being of adolescents and their parents are related, but data from non-Western countries are scarce. The aim of the present study was to investigate the relationship between adolescents' and their parents' sleep patterns and psychological functioning in northeastern Iran. A total of 81 families (81 mothers, 78 fathers, 130 children aged 12-20 years) took part in the study. They individually and separately completed questionnaires related to sleep and psychological functioning. Sleep quality was related within families. Poor sleep among children and parents was related in each case to more depressive symptoms and stress. Mothers' sleep and psychological functioning were more related to adolescent children's sleep and psychological functioning than were those of fathers. Results confirm research showing that adolescent's and parents' sleep and psychological functioning are inter-related. This association holds also true for families in northeastern Iran, suggesting that the association reflects universal features of family functioning.

Understanding Youth Antisocial Behavior Using Neuroscience through a Developmental Psychopathology Lens: Review, Integration, and Directions for Research

Youth antisocial behavior (AB) is an important public health concern impacting perpetrators, victims, and society. Functional neuroimaging is becoming a more common and useful modality for understanding neural correlates of youth AB. Although there has been a recent increase in neuroimaging studies of youth AB and corresponding theoretical articles on the neurobiology of AB, there has been little work critically examining the strengths and weaknesses of individual studies and using this knowledge to inform the design of future studies. Additionally, research on neuroimaging and youth AB has not been integrated within the broader framework of developmental psychopathology. Thus, this paper provides an in-depth review of the youth AB functional neuroimaging literature with the following goals: 1. to evaluate how this literature has informed our understanding of youth AB, 2. to evaluate current neuroimaging studies of youth AB from a developmental psychopathology perspective with a focus on integrating research from neuroscience and developmental psychopathology, as well as placing this research in the context of other related areas (e.g., psychopathy, molecular genetics), and 3. to examine strengths and weaknesses of neuroimaging and behavioral studies of youth AB to suggest how future studies can develop a more informed and integrated understanding of youth AB.

Coding task performance in early adolescence: a large-scale controlled study into boy-girl differences

This study examined differences between boys and girls regarding efficiency of information processing in early adolescence. Three hundred and six healthy adolescents (50.3% boys) in grade 7 and 9 (aged 13 and 15, respectively) performed a coding task based on over-learned symbols. An age effect was revealed as subjects in grade 9 performed better than subjects in grade 7. Main effects for sex were found in the advantage of girls. The 25% best-performing students comprised twice as many girls as boys. The opposite pattern was found for the worst performing 25%. In addition, a main effect was found for educational track in favor of the highest track. No interaction effects were found. School grades did not explain additional variance in LDST performance. This indicates that cognitive performance is relatively independent from school performance. Student characteristics like age, sex, and education level were more important for efficiency of information processing than school performance. The findings imply that after age 13, efficiency of information processing is still developing and that girls outperform boys in this respect. The findings provide new information on the mechanisms underlying boy-girl differences in scholastic performance.

Temperament and character in the Child and Adolescent Twin Study in Sweden (CATSS): comparison to the general population, and genetic structure analysis

Background

The Child and Adolescent Twin Study in Sweden (CATSS) is an on-going, large population-based longitudinal twin study. We aimed (1) to investigate the reliability of two different versions (125-items and 238-items) of Cloninger's Temperament and Character Inventory (TCI) used in the CATSS and the validity of extracting the short version from the long version, (2) to compare these personality dimensions between twins and adolescents from the general population, and (3) to investigate the genetic structure of Cloninger's model.

Method

Reliability and correlation analyses were conducted for both TCI versions, 2,714 CATSS-twins were compared to 631 adolescents from the general population, and the genetic structure was investigated through univariate genetic analyses, using a model-fitting approach with structural equation-modeling techniques based on same-sex twin pairs from the CATSS (423 monozygotic and 408 dizygotic pairs).

Results

The TCI scores from the short and long versions showed comparable reliability coefficients and were strongly correlated. Twins scored about half a standard deviation higher in the character scales. Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance, and Persistence) had strong genetic and non-shared environmental effects, while Reward Dependence and the three character dimensions had moderate genetic effects, and both shared and non-shared environmental effects.

Conclusions

Twins showed higher scores in character dimensions compared to adolescents from the general population. At least among adolescents there is a shared environmental influence for all of the character dimensions, but only for one of the temperament dimensions (i.e., Reward Dependence). This specific finding regarding the existence of shared environmental factors behind the character dimensions in adolescence, together with earlier findings showing a small shared environmental effects on character among young adults and no shared environmental effects on character among adults, suggest that there is a shift in type of environmental influence from adolescence to adulthood regarding character.

Neurocognitive correlates of obesity and obesity-related behaviors in children and adolescents

Childhood obesity rates have risen dramatically over the past few decades. Although obesity has been linked to poorer neurocognitive functioning in adults, much less is known about this relationship in children and adolescents. Therefore, we conducted a systematic review to examine the relationship between obesity and obesity-related behaviors with neurocognitive functioning in youth. We reviewed articles from 1976 to 2013 using PsycInfo, PubMed, Medline and Google Scholar. Search terms included cognitive function, neurocognitive function/performance, executive function, impulsivity, self-regulation, effortful control, cognitive control, inhibition, delayed gratification, memory, attention, language, motor, visuo-spatial, academic achievement, obesity, overweight, body mass index, waist-hip ratio, adiposity and body fat. Articles were excluded if participants had health problems known to affect cognitive functioning, the study used imaging as the only outcome measure, they were non-peer-reviewed dissertations, theses, review papers, commentaries, or they were non-English articles. Sixty-seven studies met inclusion criteria for this review. Overall, we found data that support a negative relationship between obesity and various aspects of neurocognitive functioning, such as executive functioning, attention, visuo-spatial performance, and motor skill. The existing literature is mixed on the effects among obesity, general cognitive functioning, language, learning, memory, and academic achievement. Executive dysfunction is associated with obesity-related behaviors, such as increased intake, disinhibited eating, and less physical activity. Physical activity is positively linked with motor skill. More longitudinal research is needed to determine the directionality of such relationships, to point towards crucial intervention time periods in the development of children, and to inform effective treatment programs.

Tricky teens: are they really tricky or do genetic health professionals simply require more training in adolescent health?

Providing health services to young people poses specific challenges as a consequence of their unique developmental stage. In the field of genetics, providing developmentally appropriate care can be further complicated by the familial nature of genetic information. Several fields of medicine have developed specific guidance around how best to work with adolescent patients. No such advice exists in the field of clinical genetics or genetic counseling. It is time for the field of genetics to address this aspect of practice through development of a specific adolescent-friendly model of care. Without such a model, the field risks falling behind other medical specialties and adolescents who visit genetic health professionals are at risk of missing out on best possible care.

Sleep, impulse control, and sensation-seeking predict delinquent behavior in adolescents, emerging adults, and adults

PURPOSE

The present study examined delinquent behavior from adolescence into adulthood within the dual systems model of adolescent risk-taking, which identifies maturational patterns of socioemotional and cognitive control systems as predictors of risk-taking. The role of sleep was also investigated within the relationship.

METHODS

Hierarchical regression and path analysis examined delinquency at three waves (1996, 2001, and 2008) of the National Longitudinal Study of Adolescent Health.

RESULTS

Impulse control and sensation-seeking predicted concurrent delinquent behavior at all three waves, demonstrating the developmental shift as described within the dual systems model in which the relative contribution of sensation-seeking decreases from adolescence into adulthood, whereas the relative contribution of impulse control improves. Data also revealed that sleep duration and delayed bedtimes had both direct and indirect associations with delinquent behavior during adolescence; sleep duration did not directly predict such activity during later waves.

CONCLUSION

The dual systems model of adolescent risk-taking appears to be predictive of delinquent behavior during adolescence and the transition into adulthood. Preliminary findings suggest the importance of considering both adolescent sleep and cognitive and socioemotional development during research and prevention efforts of delinquent behavior.

Impact of socio-emotional context, brain development, and pubertal maturation on adolescent risk-taking

While there is little doubt that risk-taking is generally more prevalent during adolescence than before or after, the underlying causes of this pattern of age differences have long been investigated and debated. One longstanding popular notion is the belief that risky and reckless behavior in adolescence is tied to the hormonal changes of puberty. However, the interactions between pubertal maturation and adolescent decision making remain largely understudied. In the current review, we discuss changes in decision making during adolescence, focusing on the asynchronous development of the affective, reward-focused processing system and the deliberative, reasoned processing system. As discussed, differential maturation in the structure and function of brain systems associated with these systems leaves adolescents particularly vulnerable to socio-emotional influences and risk-taking behaviors. We argue that this asynchrony may be partially linked to pubertal influences on development and specifically on the maturation of the affective, reward-focused processing system.

Working memory deficits in high-functioning adolescents with autism spectrum disorders: neuropsychological and neuroimaging correlates

Working memory is a temporary storage system under attentional control. It is believed to play a central role in online processing of complex cognitive information and may also play a role in social cognition and interpersonal interactions. Adolescents with a disorder on the autism spectrum display problems in precisely these domains. Social impairments, communication difficulties, and repetitive interests and activities are core domains of autism spectrum disorders (ASD), and executive function problems are often seen throughout the spectrum. As the main cognitive theories of ASD, including the theory of mind deficit hypotheses, weak central coherence account, and the executive dysfunction theory, still fail to explain the broad spectrum of symptoms, a new perspective on the etiology of ASD is needed. Deficits in working memory are central to many theories of psychopathology, and are generally linked to frontal-lobe dysfunction. This article will review neuropsychological and (functional) brain imaging studies on working memory in adolescents with ASD. Although still disputed, it is concluded that within the working memory system specific problems of spatial working memory are often seen in adolescents with ASD. These problems increase when information is more complex and greater demands on working memory are made. Neuroimaging studies indicate a more global working memory processing or connectivity deficiency, rather than a focused deficit in the prefrontal cortex. More research is needed to relate these working memory difficulties and neuroimaging results in ASD to the behavioral difficulties as seen in individuals with a disorder on the autism spectrum.

Inexperience and risky decisions of young adolescents, as pedestrians and cyclists, in interactions with lorries, and the effects of competency versus awareness education

BACKGROUND

Road injuries are a prime cause of death in early adolescence. Often road safety education (RSE) is used to target risky road behaviour in this age group. These RSE programmes are frequently based on the assumption that deliberate risk taking rather than lack of competency underlies risk behaviour. This study tested the competency of 10-13 year olds, by examining their decisions - as pedestrians and cyclists - in dealing with blind spot areas around lorries. Also, the effects of an awareness programme and a competency programme on these decisions were evaluated.

METHOD

Table-top models were used, representing seven scenarios that differed in complexity: one basic scenario to test the identification of blind spot areas, and 6 traffic scenarios to test behaviour in traffic situations of low or high task complexity. Using a quasi-experimental design (pre-test and post-test reference group design without randomization), the programme effects were assessed by requiring participants (n=62) to show, for each table-top traffic scenario, how they would act if they were in that traffic situation.

RESULTS

On the basic scenario, at pre-test 42% of the youngsters identified all blind spots correctly, but only 27% showed safe behaviour in simple scenarios and 5% in complex scenarios. The competency programme yielded improved performance on the basic scenario but not on the traffic scenarios, whereas the awareness programme did not result in any improvements. The correlation between improvements on the basic scenarios and the traffic scenarios was not significant.

CONCLUSIONS

Young adolescents have not yet mastered the necessary skills for safe performance in simple and complex traffic situations, thus underlining the need for effective prevention programmes. RSE may improve the understanding of blind spot areas but this does not 'automatically' transfer to performance in traffic situations. Implications for the design of RSE are discussed.