The frequency of restricted and repetitive behaviors in a community sample of 15-month-old infants.

OBJECTIVE To investigate the frequency and pattern of a wide range of restricted and repetitive behaviors in the second year of life. METHOD Parents of 139 15-month-old typically developing infants from a community sample completed the Repetitive Behavior Questionnaire-2, giving information on restricted and repetitive behaviors (e.g., stereotyped motor movements, sensory interests, routines and rituals, and preoccupations with restricted interests) seen in their children. RESULTS The Repetitive Behavior Questionnaire-2 was found to be a reliable measure of these behaviors at this age and revealed a high frequency of particular types of repetitive motor movements in 15 month olds. CONCLUSION These findings have implications for the early detection of disorders characterized by high levels of restricted and repetitive behaviors, such as autism spectrum disorder.