Irritability and stress: Prospective, bidirectional relationships in adolescence

Background: Irritability is a transdiagnostic risk factor for psychopathology and interpersonal problems in youth. However, there is little research on the role of life stress in irritability. The association between stress and irritability may be bidirectional, with irritability leading to stress exposure and stress aggravating irritability. Moreover, it is conceivable that there are sex differences in these relationships. Therefore, we examined the prospective, bidirectional relationships between irritability and stressful life events in a sample of adolescents while considering the role of biological sex. Methods: We tested multi-group path models investigating bidirectional associations of irritability with dependent and independent episodic stressors in a community sample of 520 adolescents (52.1 % male) across ages 12, 15, and 18. Results: All models had acceptable fit. For males, dependent stress at age 12 predicted irritability at age 15, which in turn predicted more stress at age 18. For females, irritability at age 12 predicted dependent stress at age 15, which in turn predicted more irritability at age 18. For independent events in males, irritability at age 15 predicted stress at age 18. For females, independent stress at age 12 predicted irritability at age 15, which in turn predicted more stress at age 18. Conclusion: There are significant bidirectional relationships between irritability and episodic stressors, although the relationships varied depending on youth's age, sex, and role in contributing to stressor occurrence.