Temporal and diagnostic influences on the expression of comorbid psychopathology symptoms in infants and toddlers with Autism Spectrum Disorder

In an attempt to increase the specificity and sensitivity the diagnostic criteria for ASD has been recently modified. Aside from the impact the diagnostic rates, these changes also have implications for the study of comorbid symptoms in the ASD population. As we refine the criteria for the ASD category we must also seek to improve our understanding of the manifestation of comorbid psychopathology within ASD populations. The current study sought to examine diagnostic and temporal influences on the expression of comorbid psychopathology symptoms in 205 infants and toddlers ranging in age from 17 to 37 months. Participants were separated into two groups based on their diagnoses (i.e., Autism Spectrum Disorder [ASD] and atypical development without an ASD). The BISCUIT-Part 2 was administered on two separate occasions, with the initial and follow up assessment occurring within one of two time intervals (4-8 months, or 9-13 months). Results from the current study indicate that the time between initial and follow up assessments is a significant factor influencing symptom expression. In addition to the temporal influence, it was observed that children diagnosed with ASD exhibit significantly less stable symptoms of comorbid psychopathology. Implications of these findings are discussed.