The adolescent brain undergoes dynamic change in neurochemistry, fiber architecture, and overall tissue composition. The course of these maturational processes is being charted with greater specificity owing to advanced in vivo neuroimaging. These techniques indicate grey matter volume reductions and protracted development of white matter in projection and association fibers known to support complex cognitive and behavioral skills. Enhancement of fronto-subcortical circuitry is notable during adolescence, though asynchronous maturation of prefrontal and limbic systems may render youth more vulnerable to risk taking, particularly in incentivized situations. This is manifest in concerning prevalence rates of substance use among adolescents. Binge-pattern alcohol consumption and comorbid marijuana use are common and associated with identifiable neural consequences. Deficits in attention, memory, and executive functioning are apparent in adolescent substance users, and are associated with alterations in prefrontal, hippocampal, and cerebellar structure and function as well as poor white matter integrity. Understanding risk and protective factors for alcohol and marijuana use in adolescents and the consequences of sustained use are the subject of ongoing study and programming efforts. The frequency of polysubstance use underscores the
