© 2015, Springer Science+Business Media New York. This study traces the developmental course of irritability symptoms in oppositional defiant disorder (ODD) from ages 3–5 and examines the psychopathological outcomes of the different trajectories at age 6. Method. A sample of 622 3-year-old preschoolers (311 were boys), followed up until age 6, was assessed yearly with a semi-structured diagnostic interview with parents and at age 6 with questionnaires answered by parents, teachers and children. Results. Growth-Mixture-Modeling yielded five trajectories of irritability levels for the whole sample (high-persistent 3.5 %, decreasing 3.8 %, increasing 2.6 %, low-persistent 44.1 % and null 46.0 %). Among the children who presented with ODD during preschool age, three trajectories of irritability symptoms resulted (high-persistent 31.9 %, decreasing 34.9 % and increasing 33.2 %). Null, low-persistent and decreasing irritability courses in the sample as a whole gave very similar discriminative capacity for children’s psychopathological state at age 6, while the increasing and high-persistent categories involved poorer clinical outcomes than the null course. For ODD children, the high-persistent and increasing trajectories of irritability predicted disruptive behavior disorders, comorbidity, high level of functional impairment, internalizing and externalizing problems and low anger control at age 6. Conclusions. Irritability identifies a subset of ODD children at high risk of poorer longitudinal psychopathological and functional outcomes. It might be clinically relevant to identify this subset of ODD children with a high number of irritability symptoms throughout development with a view to preventing comorbid and future adverse longitudinal outcomes.
- Developmental trajectories
- Oppositional defiant