Background Although children with intellectual disability (ID) seemed to be at increased risk for Attention deficit hyperactivity disorder (ADHD)/hyperactivity problems when assessed with parent report questionnaires and clinical interviews, there has been little attention to the associations between parent reports and observed child behaviours. The purpose of the present study was to compare clinical symptoms and observed impulsivity in children with ID whose parents reported them as being relatively high and low in ADHD symptoms, and to examine whether any differences were associated with developmental level.
Methods Parents of 28 children with ID completed a behaviour rating scale of hyperactivity symptoms. Parents were also interviewed using a robust clinical interview tool focused on hyperactivity symptoms. The children were all tested by an experimenter to measure their impulsive behaviour.
Results Those children with clinical range scores on parent questionnaire ratings were also reported by parents to have more ADHD symptoms using a parent report clinical interview. Although these children were also more impulsive on an experimental task, when children's developmental ages were statistically controlled impulsivity differences disappeared.
Conclusions Parent reports of ADHD symptoms in children with ID may be positively associated with data derived using clinical interview methods, but they may be less sensitive to developmental expectations when compared with observed child behaviour. Practical implications include the need for multiple sources of information and normative data for children with ID on simple experimental tasks that can be used to aid diagnosis of ADHD in clinical settings.