TRAJECTORIES OF DSM-IV SYMPTOMS OF ADHD, ODD AND ADHD+ODD IN MIDDLE CHILDHOOD: EXAMINING THE CO-VARIATION OF ADHD AND ODD SYMPTOMS AND THEIR DIFFERENTIAL PREDICTORS AND OUTCOMES
Although the importance of investigating the developmental course of problem behavior has been emphasized in the developmental psychopathology literature, few studies have examined both ADHD and ODD symptoms longitudinally to ascertain developmental changes in symptom patterns or their co-occurrence across time. Furthermore, few studies control for comorbid symptoms, making it unclear whether ADHD, ODD or their combination drive the reported associations with early risk factors and later negative outcomes. Consequently, the current study aimed to (1) explicate longitudinal patterns of DSM-IV defined ADHD and ODD symptoms and their co-occurrence across middle childhood (ages 9 to 12) using a person-centered, semi-parametric group-based modeling approach (Nagin, 1999); (2) examine the associations of trajectories of ADHD, ODD and ADHD+ODD symptoms with possible early risk factors, children's executive functioning and maternal parenting at 54 months; and (3) investigate whether academic and social outcomes at age 12 varied as a function of symptom trajectories. Prospective data were collected from birth through sixth grade from a community sample of 1081 children participating in the NICHD Study of Early Child Care and Youth Development (SECCYD). Five longitudinal patterns of ADHD symptoms were identified: very low, low, increasing, decreasing, and high stable symptom trajectories. Only three trajectories of ODD symptoms were identified: very low, low, and high stable symptom groups. The dual symptom trajectory model did not converge making it impossible to explore dual symptom trajectories. Differential associations with early risk factors and later outcomes were found after controlling for comorbid disruptive symptoms. Preschool measures of children's executive functioning predicted later levels of ADHD symptoms, but not ODD symptoms. Maternal sensitivity predicted later ODD and ADHD symptoms and harsh maternal control predicted ADHD symptoms. Later academic performance was associated with ADHD symptoms after controlling for ODD symptoms, but not with ODD symptoms alone. Finally, both ADHD and ODD symptoms were significantly associated with mother- and teacher-reported social skills. These results underscore the importance of early cognitive skills in predicting elevated ADHD symptoms and of early relationship quality in predicting symptoms of both ADHD and ODD; implications for intervention are discussed
