sábado, 27 de dezembro de 2008

Emerging Balance between Reward Systems and Risk Taking in Adolescence:

Implications for Developing Substance Abuse

Author: Linda C. Mayes, M.D., Yale University

Description
Adolescents, particularly those from high risk environments, are especially likely to engage in risky behaviors including drug use and abuse. Emotional regulation, stress responsiveness, reward sensitivity, impulse regulation, and decision-making are hypothesized to be involved in adolescent engagement in risky behaviors. Each of these capacities reflects the emerging maturation of subcortical to cortical neural circuitry involved in stress-reward systems and in the development of capacities for behavioral inhibition. During adolescence, the prefrontal cortex is relatively immature and undergoes refinement of neuronal connections. At the same time, dopaminergically regulated subcortical brain systems responsive to stress are more active in adolescence than at any other point in adulthood. Hence, in adolescence, increased dopamine input at times of increased stress may overly impair decision making and judgment in immature prefrontal circuits. This emerging balance between “emotional regulation” and “inhibition-rational decision” systems is delayed by factors such as early childhood stress or prenatal drug exposure. Thus, prenatally drug-exposed adolescents growing up in chronic adversity may be especially vulnerable to early addiction because of poor emotional regulatory mechanisms, which make them more sensitive to stress and have an attendant negative impact on inhibition, impulse control, and decision making. Understanding mechanisms for initiating drug use during a critical developmental period will allow more effective and targeted interventions for adolescents at risk for addiction.

This lecture is an installment of the Behavioral and Social Sciences Research Lecture Series sponsored by the NIH Office of Behavioral and Social Sciences Research and organized by the NIH Behavioral and Social Sciences Research Coordinating Committee. The Behavioral and Social Sciences Research Coordinating Committee (BSSR CC), with support from the Office of Behavioral and Social Sciences Research (OBSSR), convenes a series of guest lectures and symposia on selected topics in the behavioral and social sciences. These presentations by prominent behavioral and social scientists provide the NIH community with overviews of current research on topics of scientific and social interest. The lectures and symposia are approximately 50 minutes in length, with additional time for questions and discussion. All seminars are open to NIH staff and to the general public.
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