Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
Environ Health Perspect. 2010 Dec;118(12):1646-53. doi: 10.1289/ehp.1002326. Epub 2010 Sep 8.
Attention deficit/hyperactivity disorder (ADHD) is the most frequently diagnosed childhood neurobehavioral disorder. Much research has been done to identify genetic, environmental, and social risk factors for ADHD; however, we are still far from fully understanding its etiology. In this review we provide an overview of diagnostic criteria for ADHD and what is known about its biological basis. We also review the neuropsychological functions that are affected in ADHD. The goal is to familiarize the reader with the behavioral deficits that are hallmarks of ADHD and to facilitate comparisons with neurobehavioral deficits associated with environmental chemical exposures.
Relevant literature on ADHD is reviewed, focusing in particular on meta-analyses conducted between 2004 and the present that evaluated associations between measures of neuropsychological function and ADHD in children. Meta-analyses were obtained through searches of the PubMed electronic database using the terms "ADHD," "meta-analysis," "attention," "executive," and "neuropsychological functions." Although meta-analyses are emphasized, nonquantitative reviews are included for particular neuropsychological functions where no meta-analyses were available.
The meta-analyses indicate that vigilance (sustained attention), response inhibition, and working memory are impaired in children diagnosed with ADHD. Similar but somewhat less consistent meta-analytic findings have been reported for impairments in alertness, cognitive flexibility, and planning. Additionally, the literature suggests deficits in temporal information processing and altered responses to reinforcement in children diagnosed with ADHD. Findings from brain imagining and neurochemistry studies support the behavioral findings.
Behavioral, neuroanatomical, and neurochemical data indicate substantial differences in attention and executive functions between children diagnosed with ADHD and non-ADHD controls. Comparisons of the neurobehavioral deficits associated with ADHD and those associated with exposures to environmental chemicals may help to identify possible environmental risk factors for ADHD and/or reveal common underlying biological mechanisms.
注意力缺陷多动障碍（ADHD）是最常见的儿童神经行为障碍。大量研究已经确定了 ADHD 的遗传、环境和社会风险因素；然而，我们仍然远未完全了解其病因。在这篇综述中，我们提供了 ADHD 的诊断标准概述，以及对其生物学基础的了解。我们还回顾了受 ADHD 影响的神经心理学功能。我们的目标是让读者熟悉 ADHD 的行为缺陷，并促进与环境化学暴露相关的神经行为缺陷的比较。
回顾了有关 ADHD 的相关文献，特别关注了 2004 年至目前进行的元分析，这些元分析评估了儿童神经心理学功能测量与 ADHD 之间的关联。通过在 PubMed 电子数据库中使用“ADHD”、“荟萃分析”、“注意力”、“执行”和“神经心理学功能”等术语进行搜索，获得了荟萃分析。虽然强调了荟萃分析，但对于没有荟萃分析的特定神经心理学功能，也包括了非定量综述。
荟萃分析表明，被诊断患有 ADHD 的儿童在警觉性（持续性注意力）、反应抑制和工作记忆方面存在缺陷。类似但不太一致的荟萃分析结果也报告了警觉性、认知灵活性和计划方面的缺陷。此外，文献表明，被诊断患有 ADHD 的儿童在时间信息处理和对强化的反应方面存在缺陷。脑成像和神经化学研究的结果支持了这些行为发现。
行为、神经解剖学和神经化学数据表明，被诊断患有 ADHD 的儿童与非 ADHD 对照组在注意力和执行功能方面存在显著差异。将 ADHD 相关的神经行为缺陷与环境化学物质暴露相关的神经行为缺陷进行比较，可能有助于确定 ADHD 的潜在环境风险因素，或揭示潜在的共同生物学机制。
