Development of parent- and teacher-reported emotional and behavioural problems in young people with intellectual fisabilities: Does level of intellectual disability matter?
This study described similarities and differences in the 5-year stability and change of problem behaviour between youths attending schools for children with mild to borderline (MiID) versus moderate intellectual disabilities (MoID). A two-wave multiple-birth-cohort sample of 6 to 18-year-old was assessed twice across a 5-year interval using the Developmental Behaviour Checklist Primary Carer version (n = 718) and Teacher version (n = 313). For most types of problem behaviour youths with MiID and MoID showed similar levels of stability of individual differences, persistence and onset of psychopathology. Whenever differences were found, youths with MoID showed the highest level of stability, persistence and onset across informants. Mean levels of parent-reported, but not teacher-reported, problem behaviour, regardless of level of intellectual disability, decreased during the 5-year follow-up period. Youths with MoID and MiID are at risk for persistent psychopathology to a similar degree. Different informants showed to have a different evaluation of the level and the amount of change of problem behaviour, and should be considered complementary in the diagnostic process.