Symptom heterogeneity within autism spectrum disorder (ASD) is compounded by co-occurring psychopathology. Considering that some psychiatric disorders present together more often than others, deriving subgroups of individuals with ASD based on co-occurring psychopathology could better our understanding of symptom patterns existing within this population. This study's purpose was to derive subgroups of school-aged children with ASD based on co-occurring psychopathology while controlling for age

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... nd sex and to examine correlates of subgroup membership. Method: Six latent class models were estimated with a sample from the Simons Simplex Collection (n = 2,092), using dichotomized categories (borderline/clinical versus normal range) from five of the DSM-Oriented Scales of the Child Behavior Checklist for Ages 6 to 18 as indicator variables. We evaluated the predictive value of intellectual disability and three groups of medical conditions (allergies/autoimmune disorders, gastrointestinal disorders, and neurological disorders) on subgroup membership using multinomial logistic regression. Results: Four subgroups emerged based on the combined presence/absence of psychiatric symptoms: "Low Psychopathology," "Externalizing Problems," "Internalizing Problems," and "High Psychopathology." Gastrointestinal disorders, the strongest predictor, was associated with increased odds of belonging to the "Externalizing Problems," "Internalizing Problems," and "High Psychopathology" subgroups over the "Low Psychopathology" subgroup, whereas intellectual disability was associated with decreased odds. Neurological disorders was also associated with increased odds of belonging to the "Internalizing Problems" and "High Psychopathology" subgroups. Conclusion: Patterns of psychopathology exist within school-aged children with ASD and are correlated with intellectual disability as well as specific medical conditions, providing guidance for clinical practice and etiology-driven research.