Introduction

Pediatric irritability is one of the most common reasons for mental health evaluation and treatment. Irritability is transdiagnostic; while it is the hallmark symptom of disruptive mood dysregulation disorder, a new diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), it also appears in the diagnostic criteria for several mood, anxiety, and behavioral disorders and is a common correlate in others. The past 15 years have witnessed a rise in clinical neuroscience studies of pediatric irritability, resulting in significant advances in our understanding of its neural, genetic, psychophysiological, and behavioral correlates. These advances are detailed in the chapters in this volume. There is a particular focus on the implications of these findings for assessment and treatment of irritable youth, along with suggestions for further research.