Editorial: The Predictive Power of Preschool Irritability Comes Into Focus.

In recent decades, the search for early childhood markers of risk for later psychopathology has been vigorous. It has garnered escalating interest from multiple facets of developmental science, and has extended to periods as early as prenatal development. The principle that early identification of neurodevelopmental risk to target intervention during relatively higher neuroplastic periods offers a window of opportunity for larger effects and more enduring change is one key driver of this effort. Despite this intense interest and focus, the ability to test the predictive power of early markers requires time, persistence, and patience, with the later childhood and adolescent outcomes of some key longitudinal studies starting in early childhood only now becoming available. The Stony Brook Temperament Study is one such sample, from which Sorcher et al.1 report strong relationships between preschool irritability and a variety of outcomes in early adolescence, some of them surprisingly broad. Findings from this community sample demonstrate that irritability at age 3 years predicts later internalizing and externalizing outcomes as well as poor peer relations, global impairment, and health problems, even after controlling for other key established risk factors. These findings are some of the most convincing yet available to suggest that preschool irritability should be an intervention target to prevent poor long-term outcomes. However, in contrast to prior hypotheses, these data suggest that it may not be a specific marker of later affective disorders, although differences between youth and parent report were found along these lines. Surprisingly, only parent report suggested that early irritability had greater specificity to affective disorder outcomes, whereas youth self-report did not.