Integrating autism-related symptoms into the dimensional internalizing and externalizing model of psychopathology. The TRAILS Study.

Problems associated with Autism Spectrum Disorder (ASD) occur frequently in the general population and often co-occur with problems in other domains of psychopathology. In the research presented here these co-occurrence patterns were investigated by integrating a dimensional approach to ASDs into the more general dimensional framework of internalizing and externalizing psychopathology. Factor Analysis was used to develop hierarchical and bi-factor models covering multiple domains of psychopathology in three measurement waves of a longitudinal general population sample (N = 2,230, ages 10-17, 50.8% female). In all adequately fitting models, autism related problems were part of a specific domain of psychopathology that could be distinguished from the internalizing and externalizing domains. Optimal model fit was found for a bi-factor model with one non-specific factor and four specific factors related to internalizing, externalizing, autism spectrum problems and problems related to attention and orientation. Autism-related problems constitute a specific domain of psychopathology that can be distinguished from the internalizing and externalizing domains. In addition, the co-occurrence patterns in the data indicate the presence of a strong general factor.