DSM-5 symptom expression in toddlers

Although the early behaviors associated with autism spectrum disorder have been well characterized, many behaviors are also commonly observed in young children with other developmental delays and even in those with typical development. Therefore, consideration must be given to whether a child demonstrates sufficient autism spectrum disorder symptoms to warrant this diagnosis. Using the Toddler Autism Symptom Inventory, we examined caregiver endorsement of specific behaviors in three groups of toddlers referred for autism spectrum disorder risk: those who received a best-estimate diagnosis of autism spectrum disorder, those with another developmental disorder, and those who showed slight or no developmental delays and did not meet criteria for any disorder. The results revealed significant differences in symptoms among the three diagnostic groups, as well as low frequency of some DSM-5, ASD criteria, especially insistence on sameness, for those with ASD. These findings have important implications for applying the DSM-5, diagnostic criteria to toddlers. Lay abstract Children with autism show more social-communication symptoms and repetitive behaviors than children with typical development or those diagnosed with other developmental disorders; however, non-autistic children often show some behaviors that are associated with autism. We compared the behavioral reports from caregivers of children in these three groups to identify the behaviors that were specific to autism. Children with autism were found to show more of these behaviors, and behaviors that are particularly indicative of autism were identified. These behaviors included social symptoms (approaching others to interact, showing things, looking back while showing, responding to an approaching child, spontaneous imitation) and repetitive behavior symptoms (specific, inflexible play, unusual body movements, strong specific interest, carrying around an unusual object, sensory seeking, and sensory hyper-reactivity). These findings may aid professionals in determining the most appropriate diagnosis for a child between the ages of 12 and 36 months.