As the largest longitudinal study of adolescent brain development and behavior to date, the Adolescent Brain Cognitive Development (ABCD) Study® has provided immense opportunities for researchers across disciplines since its first data release in 2018. The size and scope of the study also present a number of hurdles, which range from becoming familiar with the study design and data structure to employing rigorous and reproducible analyses. The current paper is intended as a guide for researchers and reviewers working with ABCD data, highlighting the features of the data (and the strengths and limitations therein) as well as relevant analytical and methodological considerations. Additionally, we explore justice, equity, diversity, and inclusion efforts as they pertain to the ABCD Study and other large-scale datasets. In doing so, we hope to increase both accessibility of the ABCD Study and transparency within the field of developmental cognitive neuroscience.

The Adolescent Brain Cognitive Development℠ (ABCD) Study is an ongoing, diverse, longitudinal, and multi-site study of 11,880 adolescents in the United States. The ABCD Study provides open access to data about pubertal development at a large scale, and this article is a researcher’s guide that both describes its pubertal variables and outlines recommendations for use. These considerations are contextualized with reference to cross-sectional empirical analyses of pubertal measures within the baseline ABCD dataset by Herting, Uban, and colleagues (2021). We discuss strategies to capitalize on strengths, mitigate weaknesses, and appropriately interpret study limitations for researchers using pubertal variables within the ABCD dataset, with the aim of building toward a robust science of adolescent development.

Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: Increasing physical activity (PA) levels in adolescents ages 12-18 is associated with prevention of unhealthy weight gain and improvement in cardiovascular fitness. The widespread availability of mobile health (mHealth) and wearable devices offers self-monitoring and motivational features for increasing PA levels as well as improving adherence to exercise programs. Objective: The aim of this scoping review is to identify the efficacy or effectiveness of mHealth intervention strategies for facilitating PA among adolescents. Methods: We conducted a systematic search for peer-reviewed studies published between 2008 and 2017 in the following electronic databases: PubMed, Google Scholar, PsychINFO, or SportDiscus. The search terms used include (mHealth OR “mobile health” OR apps) AND (“physical activity” OR exercise) AND (children OR adolescents OR teens OR “young adults” OR kids) AND (efficacy OR effectiveness). Articles published outside of the date range (07/10/2008 – 09/01/2017) and non-English articles were removed pre-abstract review. Three reviewers assessed all abstracts against the inclusion and exclusion criteria. Any uncertainty or differences in opinion were discussed as a group. If the disagreement was still unresolved, the abstract was included in the full article review. The inclusion criteria were that the studies shall 1) have a mHealth component, 2) target participants between 12 and 18 years old, 3) have results on efficacy or effectiveness, and 4) assess PA-related outcomes. Reviews, abstracts only, protocols without results, SMS-only interventions were excluded. We also extracted potentially relevant papers from reviews. At least two reviewers examined all full articles for fit with criteria and extracted data for analysis. Data extracted from selected studies included study population, study type, components of PA intervention, and PA outcomes results. Results: 95 articles were initially identified and reviewers pulled 18 additional articles from excluded review papers. Only 15 articles were passed onto full review and 13 were kept for analysis. The included studies differed in the sizes of the study populations (11- 607 participants), locations of the study sites (7 countries), study setting, and study design. The most common measures reported were subjective weekly PA (4/13) and objective daily moderate-to-vigorous physical activity (MVPA, 4/13) of the 19 different PA outcomes assessed. Only 6/13 studies with a control or comparison group showed a significant improvement in PA outcomes between the intervention group and the control or comparison group. Of those 6, 4 permitted isolation of mHealth intervention components in the analysis. Conclusions: Our findings indicate that PA outcomes for adolescents improved over time through mHealth interventions use; however, the lack of consistency in chosen PA outcome measures, paucity of significant outcomes via between group analyses, and the weak study designs that prevent separating the effects of intervention components calls into question their true effect.

Early pubertal timing has consistently been associated with internalizing psychopathology in adolescent girls. Here, we aimed to examine whether the association between timing and mental health outcomes varies by measurement of pubertal timing and internalizing psychopathology, differs between adrenarcheal and gonadarcheal processes, and is stronger concurrently or prospectively. We assessed 174 female adolescents (age 10.0-13.0 at Time 1) twice, with an 18-month interval. Participants provided self-reported assessments of depression/anxiety symptoms and pubertal development, subjective pubertal timing, and date of menarche. Their parents/guardians also reported on the adolescent’s pubertal development and subjective pubertal timing. We assessed salivary DHEA, testosterone and estradiol levels, and conducted clinical interviews to determine the presence of case level internalizing disorders. From these data, we computed 11 measures of pubertal timing at both time points, as well as 7 measures of internalizing psychopathology, and entered these in a Specification Curve Analysis. Overall, earlier pubertal timing was associated with increased internalizing psychopathology. Associations were stronger prospectively than concurrently, suggesting that timing of early pubertal processes might be especially important for later risk of mental illness. Associations were strongest when pubertal timing was based on the Tanner Stage Line Drawings and when the outcome was case-level DSM-IV depression or HiTOP distress disorders. Timing based on hormone levels was not associated with internalizing psychopathology, suggesting that psychosocial mechanisms, captured by timing measures of visible physical characteristics, might be more meaningful determinants of internalizing psychopathology than biological ones in adolescent girls. Future research should precisely examine these psychosocial mechanisms.