Interactive Effect of Irritability and Negative Life Events on Internalizing Symptoms

Abstract

Childhood irritability and the experience of negative life events have independently been associated with the emergence and trajectory of internalizing symptoms. Here, we investigate how irritability and negative life events independently predict the course of internalizing symptoms, as well how their interaction may influence internalizing trajectories. Additionally, we examine the distinct outcomes of depressive versus anxious symptoms. Participants included 9- to 10-year-old children (N = 9,228) from the Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®). Using linear mixed effects models, we examined the course of internalizing symptoms over three years as predicted by irritability, negative life events, and their interaction. The presence of both higher irritability and negative life events independently predicted a decrease in anxious symptoms, and an increase in depressive symptoms over time. We also found that youth with higher irritability and more negative life events showed a decrease in internalizing symptoms over the course of three years. Our findings suggest that irritability and negative life events interact to predict divergent trajectories of change in internalizing symptoms. In particular, high irritability in the presence of more negative life events may promote resilience in youth against the progression of internalizing symptoms. Future work is needed to examine the specific components of irritability that may be driving this complex interaction and the underlying behavioral mechanisms that may contribute to this effect.