Brain Volumetric Correlates of Autism Spectrum Disorder Symptoms in Attention Deficit/Hyperactivity Disorder

Autism spectrum disorder (ASD) symptoms frequently occur in subjects with attention deficit/hyperactivity disorder (ADHD). While there is evidence that both ADHD and ASD have differential structural correlates, no study to date has investigated these structural correlates within a framework that robustly accounts for the phenotypic overlap between the two disorders. The presence of ASD symptoms was measured by the parent-reported Children’s Social and Behavioural Questionnaire (CSBQ) in ADHD subjects (n = 180), their unaffected siblings (n = 118) and healthy controls (n = 146). ADHD symptoms were assessed by a structured interview (K-SADS-PL) and the Conners’ ADHD questionnaires. Whole brain T1-weighted MPRAGE images were acquired and the structural MRI correlates of ASD symptom scores were analysed by modelling ASD symptom scores against white matter (WM) and grey matter (GM) volumes using mixed effects models which controlled for ADHD symptom levels. ASD symptoms were significantly elevated in ADHD subjects relative to both controls and unaffected siblings. ASD scores were predicted by the interaction between WM and GM volumes. Increasing ASD score was associated with greater GM volume. Equivocal results from previous structural studies in ADHD and ASD may be due to the fact that comorbidity has not been taken into account in studies to date. The current findings stress the need to account for issues of ASD comorbidity in ADHD.

孤独症谱系障碍（Autism Spectrum Disorder, ASD）症状常出现于注意缺陷/多动障碍（Attention Deficit/Hyperactivity Disorder, ADHD）患者群体中。尽管已有证据表明ADHD与ASD各自存在差异化的结构关联，但迄今为止尚无研究在能够稳健考量两种疾病表型重叠的严谨框架下，对二者的结构关联展开探究。本研究通过家长填写的儿童社交与行为问卷（Children’s Social and Behavioural Questionnaire, CSBQ），对ADHD患者（n=180）、未受影响的同胞（n=118）及健康对照者（n=146）的ASD症状发生情况进行评估；ADHD症状则通过结构化访谈量表（K-SADS-PL）与Conners多动症问卷进行评定。研究采集了全脑T1加权MPRAGE成像数据，并采用混合效应模型，以白质（White Matter, WM）与灰质（Grey Matter, GM）体积为自变量，对ASD症状评分的结构磁共振成像关联进行分析，模型中控制了ADHD症状水平。结果显示，相较于健康对照者与未受影响的同胞，ADHD患者的ASD症状评分显著升高；ASD评分可通过白质与灰质体积的交互作用进行预测，且ASD评分升高与灰质体积增大呈显著正相关。既往针对ADHD与ASD的结构影像学研究结果存在歧义，推测其原因在于迄今为止的相关研究均未将共病因素纳入考量范围。本研究结果强调，在ADHD相关研究中需充分重视ASD共病相关问题。