INTERNAL VALIDITY OF ATTENTION-DEFICIT HYPERACTIVITY DISORDER, OPPOSITIONAL DEFIANT DISORDER, AND OVERT CONDUCT DISORDER SYMPTOMS IN YOUNG-CHILDREN - IMPLICATIONS FROM TEACHER RATINGS FOR A DIMENSIONAL APPROACH TO SYMPTOM VALIDITY

Uses a dimensional approach to evaluate the internal validity of the a ttention deficit hyperactivity disorder (ADHD) inattention (I) and hyp eractivity/impulsivity (H/I), oppositional defiant disorder (ODD), and overt conduct disorder (CD) symptoms (i.e., whether a symptom has a s tronger correlation with its own dimension than the other three dimens ions). In Study 1, teachers rated 1,445 children on the DSM-II-R I, H/ I, ODD, and overt CD symptoms. In Study 2, teachers rated 1,711 childr en on the DSM-IV I, H/I, ODD, and overt CD symptoms. All the I symptom s showed internal validity in both studies. In contrast, the H/I sympt oms and the ODD symptoms, especially the H/I symptoms, showed weaker i nternal validity. All the overt CD symptoms showed internal validity e xcept the DSM-IV bullies others symptom, with this symptom being more strongly related to the ODD dimension. Confirmatory factor analysis pr ovided support for a 4-factor model consisting of I, H/I, ODD, and ove rt CD factors. Finally, the importance of internal validity for the co nstruct validation of the disruptive behavior symptoms is discussed.