Neurobiological processes in adolescent addictive disorders.

The purpose of this review is to summarize the neurobiological factors involved in the etiology of adolescent addiction and present evidence implicating various mechanisms in its development. Adolescents are at heightened risk for experimentation with substances, and early experimentation is associated with higher rates of SUD in adulthood. Both normative (e.g., immature frontal-limbic connections, immature frontal lobe development) and non-normative (e.g., lowered serotonergic function, abnormal hypothalamic-pituitary-adrenal axis function) neurobiological developmental factors can predispose adolescents to a heightened risk for SUD. In addition, a normative imbalance in the adolescent neurobiological motivational system may be caused by the relative underdevelopment of suppressive mechanisms when compared to stimulatory systems. These neurobiological liabilities may correspond to neurobehavioral impairments in decision-making, affiliation with deviant peers and externalizing behavior; these and other cognitive and behavioral traits converge with neurobiological factors to increase SUD risk. The progression to SUD acts as an amplifying feedback loop, where the development of SUD results in reciprocal impairments in neurobehavioral and neurobiological processes. A clearer understanding of adolescent neurobiology is a necessary step in the development of prevention and treatment interventions for adolescent SUD.