Examining the indirect contributions of irritability and chronic interpersonal stress on symptoms of anxiety and depression in adolescents

Chronic interpersonal stress has been identified as predictive of anxiety and depression. However, more research is needed to understand predictors of chronic interpersonal stress and mediators of its relationship with anxiety and depression. Irritability, a transdiagnostic symptom closely related to chronic interpersonal stress, may provide more insight into this relationship. While some research has demonstrated that irritability is related to chronic interpersonal stress, directionality is unknown. A bidirectional relationship between irritability and chronic interpersonal stress was hypothesized, such that irritability mediates the relationship between chronic interpersonal stress and internalizing symptoms and chronic interpersonal stress mediates the relationship between irritability and internalizing symptoms. This study used three cross-lagged panel models to investigate the indirect effects of irritability and chronic interpersonal stress on anxiety and depression symptoms using data from 627 adolescents (68.9 % female, 57.7 % white) over a six-year period. In partial support for our hypotheses, we found that the relationships between chronic interpersonal stress and both fears and anhedonia were mediated by irritability, and that the relationship between irritability and anhedonia was mediated by chronic interpersonal stress. Study limitations include some temporal overlap in symptom measurements, an irritability measure that has not been previously validated to measure the construct, and lack of a lifespan perspective. More targeted approaches in intervention for both chronic interpersonal stress and irritability may improve prevention and intervention efforts to address anxiety and depression.