ABSTRACT
OBJECTIVES: The objective of this study was to investigate the relationship between restricted, repetitive behaviors and interests (RRBI) and autistic symptoms in Korean high functioning autism spectrum disorder (ASD) children and to examine the structure of RRBI. METHODS: Participants included 147 high functioning ASD subjects and 181 unaffected siblings. ASD subjects were divided into two groups based on the presence of RRBI. The domain scores of the Korean version of Autism Diagnostic Interview-Revised (K-ADI-R), Korean version of Asperger Syndrome Diagnostic Scale and total scores of Korean translated version of Social Responsiveness Scale, Korean version of Social Communication Scale were used for comparison of ASD symptoms between the groups. Eleven items from the RRBI domain of the K-ADI-R were used in principal axis factor analysis (PAF). RESULTS: A statistically lower nonverbal IQ score was observed for ASD with RRBI than for ASD without RRBIs, and more social deficit, communication deficit, and behavioral and emotional problems were observed for ASD with RRBI compared to ASD without RRBI. Using PAF, two distinct factors were identified. 'Resistance to trivial changes in environment', 'Difficulty with minor changes in personal routine & environment', and 'Compulsion/ritual' were included as one factor. CONCLUSION: Analysis of the data suggests that the presence of RRBI in high functioning ASD is associated with a more severe presentation of autistic disorder. In addition, there appears to be heterogeneity within RRBI in autism except insistence on sameness.