Journal of Attention Disorders 1–10 © The Author(s) 2016 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1087054716682336 jad.sagepub.com Article Adolescence is a period characterized by increased risk- taking behaviors (Centers for Disease Control Prevention, 2010), with the prevalence of certain behaviors rising dur- ing late adolescence due to developmental transitions and increased opportunities for engagement (Brown et al., 2008; Institute of Medicine (US) and National Research Council (US) Committee on the Science of Adolescence, 2011). Prior research has identified attention/hyperactivity prob- lems (AP) during childhood, including clinical diagnoses of ADHD, to be a risk factor for engaging in risk-taking behavior during late adolescence and early adulthood (Graziano et al., 2015), as well as risky decision making on laboratory tasks (Dekkers, Popma, Agelink van Rentergem, Bexkens, & Huizenga, 2016). However, the mechanistic processes connecting these two behavioral phenotypes remain uncertain. One likely candidate is neurobiological development, as brain regions exhibiting altered develop- mental trajectories in individuals with attention problems overlap with regions implicated in risk taking. Attention problems (AP) that frequently co-occur with hyperactive and impulsive behaviors, as seen within the con- text of ADHD, are thought to be mediated by distributed brain regions, and in particular, the frontostriatal network comprising prefrontal regions and the basal ganglia (Cubillo, Halari, Smith, Taylor, & Rubia, 2012). There is also a grow- ing literature indicating that maturation of frontostriatal regions during adolescence may be related to AP during this period. For example, Shaw and colleagues demonstrated that individuals with ADHD have delayed cortical matura- tion in components of the attention network (Shaw et al., 2007). Longitudinal follow-up into adulthood identified a convergence toward normal cortical dimensions in individu- als with remitted ADHD (i.e., similar thickness to typically developing individuals), while those with persistent ADHD continued to exhibit different cortical dimensions/patterns (Shaw et al., 2013). While these findings suggest differential cortical development in ADHD, comparatively less research has focused on AP as a continuous dimension with varying levels of severity within the general population. 682336JAD XX X 10.1177/1087054716682336Journal of Attention DisordersVijayakumar et al. research-article 2016 1 University of Oregon, Eugene, USA 2 The University of Melbourne, Victoria, Australia 3 Deakin University, Geelong, Australia 4 Murdoch Childrens Research Institute, Melbourne, Australia Corresponding Author: Nandita Vijayakumar, Department of Psychology, University of Oregon, OR 97403, USA. Email: nanditav@uoregon.edu Neurodevelopmental Trajectories Related to Attention Problems Predict Driving- Related Risk Behaviors Nandita Vijayakumar 1 , Nicholas B. Allen 1,2 , George J. Youssef 3,4 , Julian G. Simmons 2 , Michelle L. Byrne 1 , and Sarah Whittle 2 Abstract Objective: Investigate neurodevelopmental trajectories related to attention/hyperactivity problems (AP) in a community sample of adolescents and whether these trajectories predict later-emerging health risk behaviors. Method: One hundred sixty-six participants underwent up to three magnetic resonance imaging (MRI) scans (n = 367) between 11 and 20 years of age. AP were measured during early adolescence using the Child Behaviour Checklist, and engagement in risk behaviors was measured during late adolescence using the “DRIVE” survey (i.e., driving risks) and items assessing alcohol-harms. Results: Greater AP scores during early adolescence were related to less reduction over time of left dorsal prefrontal, left ventrolateral prefrontal, and right orbitofrontal thickness. Less thinning of the orbitofrontal cortex was related to greater driving-related risk behaviors at late adolescence. Conclusion: Findings highlight altered neurodevelopmental trajectories in adolescents with AP. Furthermore, altered orbitofrontal development was related to later-emerging driving-related risk, and this neurobiological change mediated the association between attention problems and risk behaviors. (J. of Att. Dis. XXXX; XX(X) XX-XX) Keywords brain development, adolescence, risky behavior, attention problems, structural MRI