Adolescence is a developmental phase that is characterized by unique transformations in brain and behavior. Adolescents across a variety of species not only show increases in risk-taking and novelty seeking behaviors, but also demonstrate elevated social interactions with their peers. Brain alterations in regions implicated in mediating motivational and reward-related behaviors likely contribute to expression of these adolescent-typical behaviors. An early maturing or exaggerated reward system, perhaps associated with an augmented responsiveness of the NAc, may lead to an enhanced sensitivity to the positive hedonics of potential rewards during this developmental phase. Additional behavioral evidence suggests that adolescents may conversely exhibit an attenuated sensitivity to aversive properties of stimuli, perhaps in part through developmental alterations in neural components of these same motivational systems, although the neural mechanisms underlying such aversive properties have not been systematically explored in adolescence. Ultimately, this adolescent-typical combination of enhanced positive/attenuated aversive biases toward drugs and other stimuli may contribute to elevated drug use during adolescence. Upon first use of a novel drug, adolescents may experience positive effects in the absence of notable aversive effects (e.g.
