Chronic versus episodic irritability in youth: A community-based, longitudinal study of clinical and diagnostic associations

Objective: Irritability is both a normal developmental phenomenon and a common psychiatric symptom in children. In psychiatric nosology, a distinction is made between chronic and episodic irritability. This study examines the validity of this distinction. Methods: A sample of 776 youths received Diagnostic and Statistical Manual of Mental Disoders (DSM)-based structured interviews at three time points. Questions regarding episodic and chronic irritability were used to create scales measuring these constructs; associations with age, gender, and diagnosis were examined. Results: Episodic and chronic irritability differed in their associations with age. The longitudinal stability within irritability type was stronger than between types. In longitudinal analyses, chronic irritability at time 1 (mean age 13.8 +/- 2.6 years) predicted attention-deficit/hyperactivity disorder at time 2 (mean age 16.2 +/- 2.8 years) and major depression at time 3 (mean age 22.1 +/- 2.7 years). Episodic irritability at time 1 predicted simple phobia and mania at time 2. Conclusions: Episodic and chronic irritability in adolescents appear to be stable, distinct constructs. Further research is needed to elucidate the longitudinal associations of each with specific psychiatric diagnoses.