Conflict of interest statement: No conflicts declared.
Evidence for three subtypes of repetitive behavior in autism that differ in familiality and association with other symptoms
Article first published online: 27 OCT 2008
© 2008 The Authors. Journal compilation © 2008 Association for Child and Adolescent Mental Health
Journal of Child Psychology and Psychiatry
Volume 49, Issue 11, pages 1193–1200, November 2008
How to Cite
Lam, K. S.L., Bodfish, J. W. and Piven, J. (2008), Evidence for three subtypes of repetitive behavior in autism that differ in familiality and association with other symptoms. Journal of Child Psychology and Psychiatry, 49: 1193–1200. doi: 10.1111/j.1469-7610.2008.01944.x
- Issue published online: 27 OCT 2008
- Article first published online: 27 OCT 2008
- Manuscript accepted 17 March 2008
- repetitive behavior;
- factor analysis;
- Autism Diagnostic Interview-Revised
Background: Restricted repetitive behaviors (RRBs) are a core feature of autism and consist of a variety of behaviors, ranging from motor stereotypies to complex circumscribed interests. The objective of the current study was to examine the structure of RRBs in autism using relevant items from the Autism Diagnostic Interview-Revised in a sample of 316 individuals with autistic disorder.
Methods/Results: Using exploratory factor analysis, three distinct factors were identified: Repetitive Motor Behaviors (RMB), Insistence on Sameness (IS), and Circumscribed Interests (CI). RMB were found to be associated with a variety of subject characteristics such as IQ, age, social/communication impairments, and the presence of regression. IS was associated with social and communication impairments whereas CI appeared to be independent of subject characteristics, suggesting CI may be particularly useful in subsetting samples. Based on sib-pair correlations, IS and CI (but not RMB) appear to be familial. Analysis of the data at the case level suggests that the presence of multiple forms of RRB in an individual is associated with more impairment in the social and communication domains, suggesting a more severe presentation of autistic disorder.
Conclusions: There appears to be considerable structure within repetitive behavior in autism. The finding that these behaviors are differentially related to subject characteristics and familiality adds to their validity.