Department of Psychology, Michigan State University, East Lansing, MI 48824, USA.
J Abnorm Psychol. 2010 Feb;119(1):1-17. doi: 10.1037/a0018010.
Behavioral genetic investigations have consistently demonstrated large genetic influences for the core symptom dimensions of attention-deficit/hyperactivity disorder (ADHD), namely inattention (INATT) and hyperactivity (HYP). Yet little is known regarding potential similarities and differences in the type of genetic influence (i.e., additive vs. nonadditive) on INATT and HYP. As these symptom dimensions form the basis of the current Diagnostic and Statistical Manual of Mental Disorders subtype classification system, evidence of differential genetic influences would have important implications for research investigating causal mechanisms for ADHD. The current meta-analysis aimed to investigate the nature of etiological influences for INATT and HYP by comparing the type and magnitude of genetic and environmental influences each. A comprehensive literature search yielded 79 twin and adoption studies of INATT and/or HYP. Of these, 13 samples of INATT and 9 samples of HYP were retained for analysis. Results indicated that both dimensions were highly heritable (genetic factors accounted for 71% and 73% of the variance in INATT and HYP, respectively). However, the 2 dimensions were distinct as to the type of genetic influence. Dominant genetic effects were significantly larger for INATT than for HYP, whereas additive genetic effects were larger for HYP than for INATT. Estimates of unique environmental effects were small to moderate and shared environmental effects were negligible for both symptom dimensions. The pattern of results generally persisted across several moderating factors, including gender, age, informant, and measurement method. These findings highlight the need for future studies to disambiguate INATT and HYP when investigating the causal mechanisms, and particularly genetic influences, behind ADHD.
行为遗传学研究一直表明，注意力缺陷多动障碍（ADHD）的核心症状维度，即注意力不集中（INATT）和多动（HYP），存在较大的遗传影响。然而，对于 INATT 和 HYP 的遗传影响类型（即加性与非加性）是否存在潜在的相似性和差异，我们知之甚少。由于这些症状维度构成了当前《精神障碍诊断与统计手册》亚型分类系统的基础，如果遗传影响存在差异，这将对研究 ADHD 的因果机制具有重要意义。本研究旨在通过比较 INATT 和 HYP 的遗传和环境影响的类型和大小，来探究其病因影响的本质。通过全面的文献检索，共获得了 79 项关于 INATT 和/或 HYP 的双生子和收养研究。其中，保留了 13 项 INATT 样本和 9 项 HYP 样本进行分析。结果表明，这两个维度都具有高度遗传性（遗传因素分别占 INATT 和 HYP 变异的 71%和 73%）。然而，这两个维度在遗传影响的类型上存在差异。与 HYP 相比，INATT 的显性遗传效应显著更大，而 HYP 的加性遗传效应则大于 INATT。独特环境效应的估计值较小到中等，共享环境效应对于两个症状维度都可以忽略不计。这些结果在多种调节因素（包括性别、年龄、信息来源和测量方法）下都具有一致性。这些发现强调了未来研究在调查 ADHD 的因果机制，特别是遗传影响时，需要区分 INATT 和 HYP。
