A Narrative Review on Irritability and Its Impact on Functional Impairment in Children and Adolescents with Autism Spectrum Disorder

Irritability is a prevalent and challenging symptom in children and adolescents with autism spectrum disorder (ASD), often manifesting as temper outbursts, aggression, and low frustration tolerance. While core features of ASD include social communication deficits and restricted, repetitive behaviours, comorbid irritability can significantly exacerbate functional difficulties in daily life. Recent studies have highlighted that irritability is not only distressing for the individual but also contributes to increased caregiver stress and impedes therapeutic engagement. Importantly, it often overlaps with symptoms of anxiety, ADHD, and mood disorders, making it a complex and multifactorial issue. This symptomatology may also be a reaction to sensory sensitivities, communication barriers, or environmental stressors commonly experienced by individuals with ASD. The impact of irritability on functional impairment is multifaceted, affecting academic performance, peer relationships, family dynamics, and adaptive skills. Children and adolescents with higher irritability levels are more likely to face school exclusion, social isolation, and difficulty with self-care and community functioning. Furthermore, persistent irritability may hinder the effectiveness of behavioural and educational interventions, thereby limiting developmental progress. Interventions that target irritability, including parent training programs, behavioural therapy, and pharmacological options like atypical antipsychotics, have shown promise in improving both behaviour and overall functioning. However, more research is needed to tailor these approaches based on individual profiles and to explore the neurobiological underpinnings of irritability in ASD. Recognizing and addressing irritability as a core treatment target is essential for enhancing the quality of life and long-term outcomes for youth with autism.