Adisetiyo Vitria, Gray Kevin M
Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina.
Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina.
Am J Addict. 2017 Mar;26(2):99-111. doi: 10.1111/ajad.12500. Epub 2017 Jan 20.
BACKGROUND/OBJECTIVES: Children with attention-deficit/hyperactivity disorder (ADHD) are nearly three times more likely to develop substance use disorders (SUD) than their typically developing peers. Our objective was to review the existing neuroimaging research on high-risk ADHD (ie, ADHD with disruptive behavior disorders, familial SUD and/or early substance use), focusing on impulsivity as one possible mechanism underlying SUD risk.
A PubMed literature search was conducted using combinations of the keywords "ADHD," "substance use," "substance use disorder," "SUD," "addiction," "dependence," "abuse," "risk," "brain" "MRI," "imaging" and "neuroimaging." Studies had to include cohorts that met diagnostic criteria for ADHD; studies of individuals with ADHD who all met criteria for SUD were excluded. Eight studies met the search criteria.
Individuals with high-risk ADHD have hyperactivation in the motivation-reward processing brain network during tasks of impulsive choice, emotion processing, and risky decision-making. During response inhibition tasks, they have hypoactivation in the inhibitory control brain network. However, studies focusing on this latter circuit found hypoactivation during inhibitory control tasks, decreased white matter microstructure coherence and reduced cortical thickness in ADHD independent of substance use history.
DISCUSSION/CONCLUSIONS: An exaggerated imbalance between the inhibitory control network and the motivation-reward processing network is theorized to distinguish individuals with high-risk ADHD. Preliminary findings suggest that an exaggerated aberrant reward processing network may be the driving neural correlate of increased SUD risk in ADHD.
Neural biomarkers of increased SUD risk in ADHD could help clinicians identify which patients may benefit most from SUD prevention. Thus, more neuroimaging research on this vulnerable population is needed. (Am J Addict 2017;26:99-111).
背景/目的：患有注意力缺陷多动障碍（ADHD）的儿童发展为物质使用障碍（SUD）的可能性几乎是其发育正常的同龄人三倍。我们的目的是回顾现有的关于高危ADHD（即伴有破坏性行为障碍、家族性SUD和/或早期物质使用的ADHD）的神经影像学研究，重点关注冲动性这一可能构成SUD风险的潜在机制。
使用关键词“ADHD”、“物质使用”、“物质使用障碍”、“SUD”、“成瘾”、“依赖”、“滥用”、“风险”、“大脑”、“MRI”、“成像”和“神经影像学”的组合在PubMed上进行文献检索。研究必须纳入符合ADHD诊断标准的队列；排除所有符合SUD标准的ADHD个体的研究。八项研究符合检索标准。
高危ADHD个体在冲动选择、情绪处理和风险决策任务期间，其动机-奖赏处理脑网络呈现过度激活。在反应抑制任务期间，他们的抑制控制脑网络呈现激活不足。然而，关注后一回路的研究发现，在抑制控制任务期间，ADHD患者激活不足，白质微结构连贯性降低，皮质厚度减少，且与物质使用史无关。
讨论/结论：理论上认为，抑制控制网络与动机-奖赏处理网络之间的过度失衡可区分高危ADHD个体。初步研究结果表明，过度异常的奖赏处理网络可能是ADHD患者SUD风险增加的驱动神经关联因素。
ADHD患者SUD风险增加的神经生物标志物有助于临床医生识别哪些患者可能从SUD预防中获益最大。因此，需要对这一脆弱人群进行更多的神经影像学研究。（《美国成瘾杂志》2017年；26:99 - 111）
