Abstract
OBJECTIVE: Irritability symptoms are closely associated with, and may reflect, temperament traits, particularly negative affectivity (NA). However, there are few empirical data on the relationships between child temperament and irritability symptoms. METHOD: We investigated cross-sectional and longitudinal relationships between irritability symptoms and temperament traits from age 3-15 in a community sample of 609 children and their parents. Irritability symptoms were assessed through structured interviews with parents at ages 3/6, and inventories completed by parents and youth at ages 12/15. Temperament traits were assessed using parent reports at ages 3/6, and parent and child reports at ages 12/15. Path analysis and structural equation modeling were used to explore longitudinal associations from ages 3-6 and 12-15, respectively. RESULTS: Higher levels of irritability symptoms at ages 3/6 were concurrently associated with higher levels of NA and lower levels of effortful control (EC). In adolescence, higher irritability symptoms were concurrently associated with higher negative temperament and disinhibition. In longitudinal analyses from age 3-6 and 12-15, irritability symptoms showed modest but significant stability after adjusting for the stability of temperament traits. However, there were significant differences in the stability paths at age 3-6, reflecting lower stability of irritability symptoms. Finally, EC at age 3 predicted increased irritability symptoms at age 6, while irritability symptoms at age 3 predicted increased NA at age 6. CONCLUSION: Irritability symptoms are robustly associated with both temperamental NA and difficulty regulating attention and behavior. These findings help situate irritability symptoms within widely accepted temperament/personality taxonomies.