To examine the stability and change in oppositional defiant disorder (ODD) with onset among preschool children in a pediatric sample.

A total of 510 children aged 2–5 years were enrolled initially in 1989–1990 (mean age 3.42 years); 280 participated in five waves of data collection over a period of 48 to 72 months (mean wave 5 age, 8.35 years). Test batteries varied by age, but they included the Child Behavior Checklist, developmental evaluation, Rochester Adaptive Behavior Inventory, and a play session (before age 7 years) and a structured interview (Diagnostic Interview for Children and Adolescents, parent and child versions) at ages 7+ years. Consensus diagnoses were assigned by using best-estimate procedures.

Wave 1 single-diagnosis ODD showed a significant relationship with both single-diagnosis ODD and single-diagnosis attention-deficit hyperactivity disorder (ADHD) at subsequent waves, but not with single-diagnosis anxiety or mood disorders. Single-diagnosis ODD at wave 1 was associated with later comorbidity of ODD/ADHD, ODD/anxiety, and ODD/mood disorders. Stability across waves 2 through 5 was moderate to high for comorbid ODD/anxiety and ODD/ADHD; low to moderate stability for single-diagnosis ODD and single-diagnosis mood disorder; and low for mood disorder, single-diagnosis ADHD, and single-diagnosis anxiety disorder.

Preschool children with ODD are likely to continue to exhibit disorder, with increasing comorbidity with ADHD, anxiety, or mood disorders.