Preschool Irritability Predicts Adolescent Psychopathology and Functional Impairment: A 12-Year Prospective Study

Objective: The long-term clinical and functional outcomes of preschool-age irritability are unknown. This study examined longitudinal associations of preschool irritability with psychiatric disorders and functional impairment assessed in adolescence in a large community sample. Method: A total of 453 children were assessed at age 3 and again at ages 12 and/or 15. At age 3, parents were interviewed about their child's irritability, other psychiatric symptoms, and functional impairment with the Preschool Age Psychiatric Assessment (PAPA). In adolescence, both parents and youths were interviewed with the Schedule for Affective Disorders and Schizophrenia for School-Age Children–Present and Lifetime (K-SADS-PL) to assess youth psychopathology and functional impairment; youths also completed the UCLA Life Stress Interview (LSI) to assess different domains of functioning. Lastly, youths and parents completed the Children's Depression Inventory 2 (CDI 2) and the Screen for Child Anxiety Related Disorders (SCARED). Results: Irritability at age 3 predicted internalizing and externalizing disorders in adolescence; parent-reported anxiety and depressive symptoms; and greater functional impairment, including poorer peer functioning, poorer physical health, and antidepressant and educational service use, even after controlling for baseline psychiatric disorders. All longitudinal associations persisted after further adjusting for well-established early life risk markers for psychopathology. Conclusion: The findings of this study underscore the clinical significance and predictive power of preschool irritability and provide support for its use in large-scale identification and intervention efforts.