Preschool irritability: longitudinal associations with psychiatric disorders at age 6 and parental psychopathology.

OBJECTIVE: There is increasing scientific and clinical attention to chronic irritability in youth. However, little is known about the predictive validity and clinical significance of chronic irritability during early childhood. This prospective, longitudinal study examined associations of chronic irritability with psychiatric disorders and parental psychopathology in a large community sample of preschoolers.
METHOD: Four hundred sixty-two preschool-age children were assessed at 3 and 6 years of age. Child psychopathology was assessed at baseline (3 years) and follow-up (6 years) using a diagnostic interview, the Preschool Age Psychiatric Assessment, with parents. Items from the Preschool Age Psychiatric Assessment were used to create a dimensional measurement of chronic irritability. Parental psychopathology was assessed with a diagnostic interview at baseline.
RESULTS: Chronic irritability was concurrently associated with a wide range of psychiatric disorders and functional impairment at 3 and 6 years of age. Irritability at 3 years predicted depression, oppositional defiant disorder, and functional impairment at 6 years after controlling for baseline disorders. Irritability also was associated with parental depression and anxiety.
CONCLUSIONS: Findings underscore the central role of irritability in early-emerging mental health problems. They are consistent with longitudinal studies in older youth indicating that chronic irritability predicts later depression and anxiety and support the importance of early detection and interventions targeting preschool irritability.