Irritability in developmental age: A narrative review of a dimension crossing paediatric psychopathology.

Objective: Irritability is an important theme in paediatric psychiatry considering its high frequency in developmental age, its association with negative outcomes and consequently significant public health impact. Present as main or associated feature of several psychiatric diagnoses, irritability represents a challenge for clinicians who try to understand its origin and role in developmental psychopathology. In this review we try to: (1) get an overview of this dimension and its relationship with each of the main neuropsychiatric disorders in paediatric population and (2) provide a summary of currently available instruments to assess irritability in children and adolescents.
Method: In this narrative review, an overview of irritability in children and adolescents is proposed focusing on selected literature.
Results: Irritability as feature of many paediatric psychiatric conditions has been evaluated by many authors and included in classifications of paediatric psychiatric diseases. Framework of irritability evolved over time and dimension of irritability has been investigated using different tools and methodologies, both qualitative and quantitative. Metrics of irritability as clinical dimension are important in the diagnostic process of paediatric diseases.
Conclusion: Investigating the presence of irritability in all children with related disorders is mandatory if we consider the risk for functional impairment and affective and behavioural disorders associated with high levels of irritability. Using rigid threshold in developmental age to differentiate physiological from pathological irritability could lead many children having subthreshold levels of irritability to receive no diagnosis and, consequently, no treatment where instead a dimensional approach to irritability could allow to identify prodromal phase and prevent the evolution towards clinical pathological expressions.