Longitudinal course of behavioral and emotional problems in Williams syndrome.

A follow-up study of behavior and emotional problems in a cohort of young people with Williams syndrome 5 years after first assessment is described. Using a between-/within-subjects factorial layout, we compared scores on the Developmental Behaviour Checklist between young people with Williams syndrome and a large epidemiological control sample of young people with mental retardation due to other causes from Time 1 (1990/1991) to Time 2 (1995/1996). Results showed substantial persistence of the overall level of behavior and emotional problems. However, there were changes in certain types of behavior. Participants with Williams syndrome had significantly higher overall behavioral and emotional problems, communication disturbance, and anxiety over the 5-year period. Further, 10 or 13 checklist items maintained significantly higher levels among the Williams syndrome sample.