Assessing Irritability in Primary School-Aged Children: How to Test and Whom to Ask

<b>Background/Objectives</b>: An increasing number of children and adolescents with mental health issues across many countries highlights the need for effective, accessible prevention strategies. Within the Research Domain Criteria framework, irritability-an emotional response to expected but blocked rewards-has been identified as an early indicator of declining mental well-being before the onset of mental disorders. Developing reliable yet resource-efficient methods to assess irritability is an important first step toward targeted prevention. <b>Methods</b>: We tested the German Version of a frustration Go/No-Go task enabling to deliberately induce frustration through expected but blocked rewards in N = 68 children aged eight to ten (mean age = 8.9 years, SD = 0.7; 36 females) and parallelly assessed irritability with the 7-item low cost Affective Reactivity Index (ARI) with ratings of parents, teachers and children. <b>Results</b>: The German Version of the frustration Go/No-Go task proved reliable and valid. Teacher ratings demonstrated the highest predictive validity for irritability among all informants. <b>Conclusions</b>: Both the 7-item ARI, rated by teachers, and the frustration Go/No-Go task are recommended for assessing irritability. In the future, irritability assessments should be implemented for all primary school-aged children. Based on the components that contribute to irritability, targeted prevention measures should be offered.