OBJECTIVE The two primary-seemingly contradictory-strategies for classifying child psychiatric syndromes are categorical and dimensional; conceptual ambiguities appear to be greatest for polythetic syndromes such as autism spectrum disorder (ASD). Recently, a compelling alternative has emerged that integrates both categorical and dimensional approaches (ie, a hybrid model), thanks to the increasing sophistication of analytic procedures. This study aimed to quantify the optimal phenotypic structure of ASD by comprehensively comparing categorical, dimensional, and hybrid models. METHOD The sample comprised 3,825 youth, who were consecutive referrals to a university developmental disabilities or child psychiatric outpatient clinic. Caregivers completed the Child and Adolescent Symptom Inventory-4R (CASI-4R), which includes an ASD symptom rating scale. A series of latent class analyses, exploratory and confirmatory factor analyses, and factor mixture analyses was conducted. Replication analyses were conducted in an independent sample (N = 2,503) of children referred for outpatient evaluation. RESULTS Based on comparison of 44 different models, results indicated that the ASD symptom phenotype is best conceptualized as multidimensional versus a categorical or categorical-dimensional hybrid construct. ASD symptoms were best characterized as falling along three dimensions (ie, social interaction, communication, and repetitive behavior) on the CASI-4R. CONCLUSION Findings reveal an optimal structure with which to characterize the ASD phenotype using a single, parent-report measure, supporting the presence of multiple correlated symptom dimensions that traverse formal diagnostic boundaries and quantify the heterogeneity of ASD. These findings inform understanding of how neurodevelopmental disorders can extend beyond discrete categories of development and represent continuously distributed traits across the range of human behaviors.

中文翻译：

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量化自闭症表型的最佳结构：对维度，分类和混合模型的综合比较。

目的对儿童精神病综合症进行分类的两个主要看似矛盾的策略是分类和维度。对于诸如自闭症谱系障碍（ASD）之类的综合症候群，概念上的歧义似乎最大。近来，由于分析程序的日益复杂化，已经出现了一种令人信服的替代方法，该方法将分类方法和维度方法（即混合模型）集成在一起。本研究旨在通过综合比较分类，维数和混合模型来量化ASD的最佳表型结构。方法样本包括3,825名青年，他们是连续转诊至大学发育障碍或儿童精神科门诊的。照顾者填写了《儿童和青少年症状清单4R》（CASI-4R），其中包括ASD症状评分量表。进行了一系列潜在类别分析，探索性和确认性因子分析以及因子混合分析。在接受门诊评估的儿童的独立样本（N = 2,503）中进行了复制分析。结果基于对44种不同模型的比较，结果表明ASD症状表型最好被概念化为多维与分类或分类维混合结构。ASD症状的最佳特征是在CASI-4R上沿三个维度（即社交互动，沟通和重复行为）下降。结论研究结果揭示了一种最佳结构，可通过一项单一的父母报告测度来表征ASD表型，支持跨越相关的诊断边界并量化ASD异质性的多个相关症状维度的存在。这些发现有助于人们理解神经发育障碍如何扩展到离散的发展类别之外，并代表人类行为范围内持续分布的特征。