注意缺陷多动障碍与品行障碍共病机制的双生子研究

目的 研究遗传因素和环境因素的相互作用对于注意缺陷多动障碍和品行障碍共病的影响.方法 利用已经建立的西南地区双生子随访登记系统,采用定量行为遗传学研究方法,用《困难和长处量表》父母评定的注意缺陷多动和品行问题分量表分作为定量表型,收集140对6～16岁双生子的临床资料,构建双生子行为表型的单因素和二因素结构方程模型,分析变量内双生子间、变量间双生子内以及变量间双生子间的相关性,基于模型的似然值和拟合度寻找最优模型,阐明遗传因素、共享的环境因素以及非共享的环境因素对于注意缺陷多动障碍和品行障碍共病的影响.结果 注意缺陷多动和品行问题的表型相关性为0.44(95% CI:0.09～0.27),其中遗传因素在二者总的表型相关性中占70%,非共享的环境因素占30%.对相关变量构建二因素结构方程模型并进行多个模型拟合,对寻找出的最优模型分析发现,注意缺陷多动和品行问题遗传相关性为0.76(95% CI:0.31～1),而个体特异性环境相关性为0.28(95% CI:0.02～0.51).结论 儿童存在3种不同的遗传因素影响注意缺陷多动障碍和品行障碍的发生,即单纯影响注意缺陷多动障碍的遗传因素、单纯影响品行障碍的遗传因素和对二者同时发生作用的遗传因素.本研究结果提示大部分作用于注意缺陷多动障碍的环境因素不会导致品行障碍的发生,即二者缺乏共同的环境因素.

Examining the comorbidity of attention deficit and hyperactivity disorder and conduct disorder in a population based twin sample

OBJECTIVE: To examine three possible causes of the relationship between attention deficit and hyperactivity disorder and conduct disorder: additive genetic factors(A), common environmental factors(C) and individual-specific environmental factors(E). METHODS: One hundred and forty pairs of twins from the Southwestern China Twin Registry were examined with the parent-rated Strength and Difficulties Questionnaire (SDQ). The cross-twin within-variable, within-twin cross-variable and cross-twin cross-variable correlations were calculated. Using structural equation modelling, bivariate models were fitted. The best fitting model was chosen based on likelihood and parsimony. RESULTS: The observed phenotypic correlation between HYPER and COND was 0.44 (95% CI: 0.09, 0.27), with genetic factors accounting for about 70% of the observed correlation. Bivariate model fitting quantified the genetic correlation between HYPER and COND at 0.76 (95% CI: 0.31, 1) and the individual-specific environmental correlation at 0.28 (95% CI: 0.02, 0.51). CONCLUSION:In children, three different genetic factors may exist: one that solely affects the liability to hyperactivity behaviour, one that has only an effect on conduct behaviour and one that influences both hyperactivity and conduct behaviour. Our results suggests that most of the environmental factors that increase the risk of hyperactivity behaviour do not influence conduct behaviour and vice versa.