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Background: Adolescence, a developmental period characterized by significant changes in sleep, is associated with normative increases in impulsivity. While short sleep duration has been linked to elevated impulsivity, the neural mechanism underlying the relationship between short sleep duration and elevated impulsivity remains poorly understood. Methods: We analyzed a dataset of 7,884 drug‐naive 9–10 year‐olds from the Adolescent Brain Cognitive Development (ABCD) study. Among them, 5,166 have two‐year follow‐up neuroimaging data. Linear mixed‐effects models, mediation analyses, and longitudinal mediation analyses were used to investigate the relationship between parent‐reported sleep duration, impulsivity, and functional and structural connectivity between the cortex and the striatum. Results: We found that less sleep duration is significantly associated with higher positive and negative urgency, which are two affect‐related components of impulsivity. In addition, we observed a link between short sleep duration and reduced corticostriatal connectivity. Neural pathways associated with short sleep duration—functional connectivity between the cingulo‐opercular network and the left caudate, and between the cingulo‐parietal network and the right pallidum—mediated the association between sleep duration and positive urgency both at baseline and two‐year follow‐up. Longitudinal mediation analyses further revealed that short sleep duration and elevated positive urgency exacerbated each other through these two corticostriatal connectivities. Conclusions: These findings highlight the key role of corticostriatal connectivities in the reciprocal relationship between short sleep duration and elevated impulsivity. Given the increasing prevalence of short sleep duration in adolescents, the link between sleep duration, impulsivity, and corticostriatal connectivities has important implications for timely interventions to address impulsive problems in early adolescents. [ABSTRACT FROM AUTHOR]

This study followed up ADHD/autistic symptoms and attentional performance in children/adolescents with ASD and typically developing ones (TD) over 5–7 years. The participants were stratified by age at baseline into child (< 12 years) and adolescent (12–19 years) groups. ADHD symptoms, especially hyperactivity, and attentional functions significantly improved during follow-up, more in children than in adolescents, in both ASD and TD. Significantly more omission errors and perseverations were noted in ASD than TD through the follow-up. Children with ASD had more improvement in reaction time while adolescents with ASD had less improvement in commission errors and detectability than TD. No correlation of attentional functions and ADHD symptoms in ASD implied different neural mechanisms of ADHD symptoms between ASD and ADHD. [ABSTRACT FROM AUTHOR]

Applying both latent variable and network frameworks, we conducted a comprehensive psychometric evaluation of the diverse array of symptoms from three externalizing dimensions, including attention problems, aggressive behavior, and delinquency/rule-breaking of the Child Behavior Checklist (Achenbach, 1991) across six time points from childhood to early adolescence. We also examined sex differences. Participants (N = 1,339) were drawn from two multisite longitudinal studies: Fast Track and the Child Development Project. Parents reported on externalizing psychopathology in kindergarten and Grades 1, 2, 4, 5, and 7. Using exploratory structural equation modeling, we found almost uniformly excellent fit across time and samples. However, we also observed multiple cross-loadings and heterogeneity in terms of which symptoms cross-loaded across time points. Alternatively, using network modeling, we observed that symptoms of attention problems and aggressive behavior had stronger connections, relative to delinquency/rule-breaking, across time and samples. Significant differences in overall connectivity were found at early (kindergarten vs. Grade 1, Grade 1 vs. Grade 2) and late (Grade 5 vs. Grade 7) time points for the combined sample and only late time points for the male sample. In addition, the items impulsive and lies or cheats consistently displayed the greatest bridge strength, that is, symptom from one dimension that connects to symptoms from another dimension, across time and samples. Our results illustrate how two methods-latent variable and network modeling-provide important and complementary information on multidimensional constructs. Findings also inform understanding of externalizing psychopathology through childhood to early adolescence by identifying key symptoms, critical transition points, and possible transdiagnostic liabilities. (PsycInfo Database Record (c) 2022 APA, all rights reserved). [ABSTRACT FROM AUTHOR]

This study aimed to estimate nitrogen balance and protein requirements in adolescent sprint athletes as a function of growth rate and physical development. Sixty adolescent sprint athletes were followed up biannually over a 2-yr period. Individual growth curves and age at peak height velocity were determined. Skeletal muscle mass (SMM) was estimated based on anthropometric measurements and fat mass was estimated by underwater densitometry. Seven-day diet and physical activity diaries were completed to estimate energy balance and protein intake. Nitrogen analysis of 24-hr urine samples collected on 1 weekday and 1 weekend day allowed calculation of nitrogen balance. Body height, weight, and SMM increased throughout the study period in both genders. Mean protein intakes were between 1.4 and 1.6 g kg-1 day-1 in both genders. A protein intake of 1.46 g kg-1 day-1 in girls and 1.35 g kg-1 day-1 in boys was needed to yield a positive nitrogen balance. This did not differ between participants during and after their growth spurt. None of the growth parameters was significantly related to nitrogen balance. It can be concluded that a mean protein intake around 1.5 g kg-1 day-1 was sufficient to stay in a positive nitrogen balance, even during periods of peak growth. Therefore, protein intake should not be enhanced in peak periods of linear or muscular growth. [ABSTRACT FROM AUTHOR]

This study aimed to provide insight into the development of postural control abilities in youth. A total of 276 typically developing adolescents (155 males, 121 females) with a mean age of 13.23 years (range of 7.11-18.80) were recruited for participation. Subjects performed two-minute quiet standing trials in bipedal stance on a force plate. Center of pressure (COP) trajectories were quantified using Sample Entropy (SampEn) in the anterior-posterior direction (SampEn-AP), SampEn in the medial-lateral direction (SampEn-ML), and Path Length (PL) measures. Three separate linear regression analyses were conducted to predict the relationship between age and each of the response variables after adjusting for individuals' physical characteristics. Linear regression models showed an inverse relationship between age and entropy measures after adjusting for body mass index. Results indicated that chronological age was predictive of entropy and path length patterns. Specifically, older adolescents exhibited center of pressure displacement (smaller path length) and less complex, more regular center of pressure displacement patterns (lower SampEn-AP and SampEn-ML values) compared to the younger children. These findings support prior studies suggesting that developmental changes in postural control abilities may continue throughout adolescence and into adulthood. [ABSTRACT FROM AUTHOR]

Background: Bipolar disorder (BD) is a severe mental illness that can have high costs for youths (<18 years old) and adults. Relative to healthy controls (HC), individuals with BD often show impaired attention, working memory, executive function, and cognitive flexibility (the ability to adapt to changing reward/punishment contingencies). In our study of youths and young adults with BD, we investigated 1) how cognitive flexibility varies developmentally in BD, and 2) whether it is independent of other executive function deficits associated with BD.Methods: We measured errors on a reversal-learning task, as well as spatial working memory and other executive function, among participants with BD (N=75) and HC (N=130), 7-27 years old. Regression analyses focused on the effects of diagnosis on reversal-learning errors, controlling for age, gender, IQ, spatial span, and executive function. Similar analyses examined non-reversal errors to rule out general task impairment.Results: Participants with BD, regardless of age, gender, or cognitive ability, showed more errors than HC on the response reversal stages of the cognitive flexibility task. However, participants with BD did not show more errors on non-reversal stages, even when controlling for other variables.Limitations: Study limitations include the cross-sectional, rather than longitudinal, design; inability to measure non-linear age effects; and inclusion of medicated participants and those with psychiatric comorbidity.Conclusions: Individuals with BD show a specific impairment in reversing a previously rewarded response, which persists across the transition from childhood to young adulthood. Tailored interventions targeting this deficit may be effective throughout this developmentally turbulent time. [ABSTRACT FROM AUTHOR]