Preschool irritability predicts child psychopathology, functional impairment, and service use at age nine.

BACKGROUND Little is known about the predictive validity and clinical significance of chronic irritability during early childhood. This prospective, longitudinal study examined associations of preschool chronic irritability with psychiatric disorders, functional impairment, and service use at age nine in a large community sample. METHODS Four hundred and forty-six children were assessed at age three and again at age nine. Child psychopathology and functional impairment were assessed at age three with the Preschool Age Psychiatric Assessment (PAPA) with parents and at age nine with the Kiddie-Schedule of Affective Disorders and Schizophrenia (K-SADS) with parents and children. Items from the PAPA were used to create a dimensional measure of chronic irritability at age three. At age nine, mothers, fathers, and youth completed the Child Depression Inventory (CDI) and the Screen for Anxiety Related Disorders (SCARED). RESULTS Chronic irritability at age three predicted any current and lifetime anxiety disorders at age nine, current and lifetime generalized anxiety disorder, and current separation anxiety, after controlling for baseline anxiety disorders. In addition, preschool irritability predicted increases in anxiety and disruptive behavior disorder symptoms on the K-SADS, and maternal and paternal reports of depressive and anxiety symptoms on the CDI and SCARED. Lastly, preschool irritability predicted greater functional impairment and outpatient treatment use, even after controlling for all psychiatric disorders at baseline. CONCLUSIONS Findings underscore the central role of irritability in developmental psychopathology and support the importance of early detection and interventions targeting preschool irritability.