Adolescent Behavioral Health Research Program, Indiana University School of Medicine, Indianapolis, Indiana.
Adolescent Behavioral Health Research Program, Indiana University School of Medicine, Indianapolis, Indiana.
J Am Acad Child Adolesc Psychiatry. 2021 May;60(5):575-576. doi: 10.1016/j.jaac.2020.12.018. Epub 2020 Dec 21.
It has been difficult to disentangle factors conferring vulnerability to substance use disorders (SUDs) from the consequences of substance use. Reward sensitivity and impulsivity have been identified as adolescent risk factors that confer vulnerability for later problematic substance use. Studies also suggest, however, that substance use itself affects brain development and behavior and that some of the same risk factors that predispose youth to SUD (eg, reward sensitivity and impulsivity) may be brought on or worsened by the neurotoxicity of drugs of abuse. Studies examining neural and behavioral correlates of SUDs commonly include youth with varying degrees of substance exposure; thus development of vulnerabilities to substance abuse are difficult to separate from the effects of substance use. In this issue of JACC, Ivanov et al. advance our field's knowledge in this area by leveraging longitudinal data from the European IMAGEN dataset (n = 2,200) in order to characterize predictors of alcohol use at age 16 as well as trajectories of impulsivity. This design allows investigation into whether alcohol drinking in adolescence may actually be related to worsening impulsivity. The authors followed a subset of the IMAGEN sample, 304 substance-naïve 14-year-olds over 2 years. Reward system function in the brain was assessed at baseline by collecting functional magnetic resonance imaging scans during a Monetary Incentive Delay (MID) task which assessed neural response to reward anticipation and outcome. Impulsivity and delay discounting, the propensity to select smaller immediate rewards versus larger, delayed rewards, were also assessed at baseline and follow-up. Linear regression was used to evaluate longitudinal associations among the frequency of alcohol use at age 16 and impulsivity, delay discounting, and reward system function at age 14. Reward system function was measured by activation in medial orbitofrontal cortex (mOFC) and ventral striatum regions of interest during the highest versus the lowest reward levels on the MID task. These regions are involved in key aspects of reward processing, including valuation of rewarding stimuli and outcomes..
将青少年期的奖赏敏感性和冲动性等风险因素确定为易患以后出现问题性物质使用的易感性因素，已经很难将导致物质使用障碍（SUD）的因素与物质使用的后果区分开来。然而，研究还表明，物质使用本身会影响大脑发育和行为，而一些使年轻人易患 SUD 的相同风险因素（例如，奖赏敏感性和冲动性）可能会因滥用药物的神经毒性而产生或恶化。研究 SUD 的神经和行为相关性的通常包括具有不同程度物质暴露的青少年；因此，物质滥用易感性的发展很难与物质使用的影响分开。在本期 JACC 中，Ivanov 等人通过利用欧洲 IMAGEN 数据集的纵向数据（n=2200），在这一领域推进了我们的知识，以描述 16 岁时饮酒的预测因素以及冲动性的轨迹。这种设计允许研究青少年时期的饮酒是否实际上与冲动性恶化有关。作者对 IMAGEN 样本的一个子集进行了随访，即 304 名 14 岁的物质未滥用的青少年，随访时间为 2 年。在基线时，通过在货币激励延迟（MID）任务中收集功能磁共振成像扫描来评估大脑中的奖赏系统功能，该任务评估了对奖赏预期和结果的神经反应。在基线和随访时还评估了冲动性和延迟折扣，即选择较小的即时奖励而不是较大的延迟奖励的倾向。线性回归用于评估 16 岁时饮酒频率与 14 岁时冲动性、延迟折扣和奖赏系统功能之间的纵向关联。通过在 MID 任务中最高与最低奖赏水平之间的内侧眶额皮层（mOFC）和腹侧纹状体的兴趣区来测量奖赏系统功能的激活。这些区域涉及奖赏处理的关键方面，包括奖赏刺激和结果的估值。
