Factor analysis of repetitive behaviors in autism as measured by the Y-BOCS

The authors carried out a factor analysis of the Yale-Brown Obsessive-Compulsive Scale checklist at the category level in order to reduce the number of variables in this domain and ultimately identify possible endophenotypes; 181 children with autism were enrolled. The authors estimated a tetrachoric correlation matrix among the dichotomous symptom categories and then used exploratory and confirmatory factor analyses to identify a clinically meaningful factor structure for this correlation matrix. Their analysis supported a four-factor solution: obsessions, higher-order repetitive behaviors, lower-order repetitive behaviors, and hoarding. These findings are another step in the effort to identify genetically and biologically distinct groups within this population.