In order to examine the importance of a range of potential risk factors for behaviour problems in children with severe intellectual disability, a sample was identified by the administration of a screening version of the Vineland Adaptive Behaviour Scales (VABS) to the parents of children aged 4-11 years attending six special needs schools in three adjacent inner London boroughs. Parents whose children had a VABS standard score of < or = 50 were interviewed using the Disability Assessment Schedule and both parents and teachers completed the Aberrant Behaviour Checklist. Most behaviour problems were more common in ambulant children, but problems less dependent on the ability to walk, such as sleeping difficulties, screaming and self-injury, were equally common in ambulant and non-ambulant children. Among ambulant children, there were few significant associations between the severity of the child's behaviour problems and the age or sex of the child, the presence or absence of epilepsy, and various indices of socio-economic disadvantage. Sleeping difficulties, overactivity, self-injury, destructive behaviour and autistic features, such as social withdrawal and stereotypies, were strongly associated with skills deficits, but aggression, temper tantrums and general disruptive behaviour were not. Limitations in daily living skills were better predictors of behaviour problems than were poor communication skills.

Neurofibromatosis-1 is the most common single gene disorder affecting 1 in 3000. In children, it is associated not only with physical features but also with attention and learning problems. Research has identified a downward shift in intellectual functioning as well, but to date, there are no published studies about the everyday adaptive behavior of children with NF1. In this study, parental reports of adaptive behavior of 61 children with NF1 ages 3 through 8 were compared to an unaffected contrast group (n = 55) that comprised siblings and community members. Significant group differences in adaptive skills were evident and were largely related to group differences in intellectual functioning. In a subsample of children with average-range intellectual functioning, group differences in parent-reported motor skills were apparent even after controlling statistically for group differences in intellectual functioning. The implications of the findings for the care of children with NF1 are discussed.