Taxonomic Examination of ADHD and Conduct Problem Comorbidity in Elementary School Children Using Cluster Analyses

Abstract

Cluster analysis was used to investigate the classification of comorbid Attention Deficit Hyperactivity Disorder (ADHD) +Conduct Problems (CP). Teachers rated 1394 elementary school children on symptoms of inattention, hyperactivity/impulsivity, opposition, and conduct problems using the ADS-IV behavior-rating scale. Results suggested that a seven-cluster solution, including two distinct comorbid clusters, was the most appropriate method of classifying children according to behavioral symptoms. A one-way MANOVA showed that overall cluster profiles differed significantly from each other, whereas one-way ANOVAs indicated that clusters differed on age and symptom scores. Chi-square analyses indicated that clusters differed on gender. Post hoc analyses and effect sizes calculations revealed that the comorbid clusters differed from each other and from their single-disorder counterparts on some variables, but not on all. These results provide support for an additive conceptualisation of ADHD +CP.