The usefulness of Conners' Rating Scales-Revised in screening for Attention Deficit Hyperactivity Disorder in children with intellectual disabilities and borderline intelligence

Background Symptoms of Attention Deficit Hyperactivity Disorder (ADHD) are believed to be common in children with intellectual disabilities (ID). Conners' Rating Scales are widely used for screening ADHD among children who do not have ID, but little is known about their usefulness among children with ID. Aims To find cut-off scores for the Conners' Parent Rating Scales-Revised (CPRS-R) and the Conners' Teacher Rating Scale-Revised (CTRS-R) that will give optimum levels of sensitivity and specificity for screening for ADHD among children with ID and borderline intelligence. Method Receiver operating characteristic analysis was used to compare a clinical diagnosis of ADHD according to the Diagnostic and Statistical Manual 4th revision-Text Review criteria with scores according to the CPRS-R and the CTRS-R. Results Among children with ID, a CPRS-R total score of 42 provided a sensitivity of 0.9 and a specificity of 0.67 with an area under the curve of 0.84. Similarly, a CTRS-R total score of 40 provided a sensitivity of 0.69 and a specificity of 0.67 with an area under the curve of 0.71. There was poor concordance between the CPRS-R and the CTRS-R total scores (Intraclass Correlation; ICC = 0.17). There were statistically significant differences in the total score of the CPRS-R and most of its sub-scores between children with ID with and without ADHD. The CTRS-R total score and its sub-scores did not show any statistically significant difference between two groups. Factor analysis showed three clinically distinct factors for both the CPRS-R and the CTRS-R items, although the CPRS-R factors were better and had less item overlap than the CTRS-R factors. Conclusions The CPRS-R scores may distinguish between children with ID with and without ADHD but not the CTRS-R scores. Many items in the CPRS-R and the CTRS-R are not applicable to children with severe and profound ID who do not have speech. The CPRS-R and the CTRS-R scores did not correlate with each other. There is a need to develop an ADHD screening instrument specifically for children with ID.