Editorial: A Call for Developmental Psychopathology Approaches to Diagnostic Nosology.

The publication of DSM-5 came with a number of significant advances, including shifts in disorder classifications and a new focus on dimensional assessment.1 It also introduced disruptive mood dysregulation disorder (DMDD), which was met with some criticism and concern. Although there was research to support the establishment of this new diagnosis aimed at improving classification of children and adolescents with persistent and impairing irritability,2 specific symptoms and definitions of frequency and impairment were not as empirically supported, and concerns arose regarding validity and reliability.3 The introduction of new diagnoses is a complex endeavor, particularly for disorders affecting children and adolescents, which require consideration of the immense neural, cognitive, and emotional changes occurring during this developmental period. Rigorous approaches grounded in developmental psychopathology are needed to establish a meaningful and clinically useful set of symptoms and associated characteristics. This is the approach that Wiggins et al.4 take to address the applicability of the DMDD diagnosis for children below the age of 6 years. Although this minimum age was included in DSM-5 to prevent unwarranted labeling of young children for whom temper outbursts are common,5 it fails to consider growing evidence of impairing irritability in preschoolers and limits identification of children who would benefit from early interventions. In response to this, these authors take a comprehensive bottom-up approach to empirically identify symptoms and to define limits of clinical severity, tailored specifically to preschool-aged children. As such, this study serves as a model of how to develop and to refine the diagnostic nosology of child psychiatric disorders.