16.2 DIAGNOSTIC ATTRIBUTIONS OF IRRITABILITY IN NEURODEVELOPMENTAL DISORDERS

Abstract

The objective of this presentation is to identify symptoms and underlying mechanisms of irritability in youth with autism spectrum disorder (ASD) and ADHD. A review of the literature on irritability in ASD and ADHD, as well as experiences of working with youth with ASD and ADHD, will be utilized to generate a diagnostic and therapeutic approach toward youth with neurodevelopmental disorders and irritability and their families. While irritability is a common and impairing symptom in youth with ASD and/or ADHD, there is inadequate research on its features and fundamental mechanisms in these youth. Moreover, a number of studies have tested the effects of pharmacological interventions on aggression and irritability in ASD and ADHD without addressing underlying processes. Evidence suggests that irritability can be reliably measured in neurodevelopmental disorders and is not a fundamental feature of neurodevelopmental disorders despite being often correlated with ASD and ADHD symptom severity and overall functional capacity. In fact, as in neurotypical peers, irritability continues to be most associated with anxiety, depression, and overall arousal in youth with ASD or ADHD and predicts greater rates of suicide and self-harm. Particularly for youth with ASD for whom deficits in social communication are central, determining the underlying causes of irritability can be challenging and crucial. Sensory overresponsivity, rigidity, and dysautonomia may all play a role. Therefore, psychoeducation for both youth and their families can be especially important in developing appropriate strategies and coping skills over time. ASD comprises a vastly heterogeneous group, so example cases of nonverbal, high-functioning, and female youth with ASD will be highlighted. To appropriately address irritability in youth with ASD and ADHD, underlying mechanisms and comorbidities must be evaluated within an individualized approach to care.