ORIGINAL RESEARCH Childhood ODD and ADHD Behavior: The Effect of Classroom Sharing, Gender, Teacher Gender and Their Interactions

Abstract One criterion for a diagnostic and statistical manual of mental disorders (DSM-IV) diagnosis of atten-tion deficit hyperactivity disorder (ADHD) and opposi-tional defiant disorder (ODD) is that symptoms are present in at least two settings, and often teacher ratings are taken into account. The short Conners ’ Teacher Rating Scales— Revised (CTRS-R) is a widely used standardized instru-ment measuring ODD and ADHD behavior in a school setting. In the current study CTRS-R data were available for 7, 9 and 12-year-old twins from the Netherlands Twin Register. Measurement invariance (MI) across student gender and teacher gender was established for three of the four scales (Oppositional Behavior, Hyperactivity and ADHD Index) of the CTRS-R. The fourth scale (ATT) showed an unacceptable model fit even without constraints on the data and revision of this scale is recommended. Gene-environment (GxE) interaction models revealed that heritability was larger for children sharing a classroom. There were some gender differences in the heritability of ODD and ADHD behavior and there was a moderating effect of teacher’s gender at some of the ages. Taken to-gether, this indicates that there was evidence for GxE in-teraction for classroom sharing, gender of the student and gender of the teacher