The Developmental Behaviour Checklist (DBC) was completed by parents and caregivers of 107 people with severe ID and 22 people with profound ID at four time periods across 12 years. Regression analyses were used to examine trends in sub-scale scores across time and groups.
Forster, S., Gray, K., Taffe, J.
, Einfeld, S., & Tonge, B.
(2011). Behavioural and emotional problems in people with severe and profound intellectual disability
. Journal of Intellectual Disability Research
(2), 190 - 198. https://doi.org/10.1111/j.1365-2788.2010.01373.x