An empirically based alternative to DSM-5's disruptive mood dysregulation disorder for ICD-11

Abstract

The World Health Organization (WHO)'s priorities for the development of the classification of mental and behavioural disorders in the ICD-11 include increasing its clinical utility in global mental health settings 1 and improving the identification and diagnosis of mental disorders among children and adolescents 2. An issue that has been hotly debated in the area of childhood psychopathology is the assessment, diagnosis and treatment of children with severe irritability and anger 3, 4. Although virtually all children display irritable and angry behaviours at times, some children exhibit them more frequently and more intensely, to the extent that they become an impairing form of emotional dysregulation. Recent findings indicate that these children with chronic and severe irritability/anger have not been adequately identified through existing classification systems, are at an increased risk for particular negative outcomes, and have not received appropriate treatment. To the extent that ICD-11 can help clarify the clinical picture of irritability/anger, children and families will benefit from more accurate diagnoses, more useful prognoses, and more effective interventions. This paper provides a brief overview of the issue, followed by several possible options and the current proposal for the classification of childhood irritability/anger in ICD-11. This proposal represents a markedly different – but we believe more scientifically justifiable – solution to the problems in this area than that selected for DSM-5 5. One of the major reasons why researchers and practitioners have been concerned about the classification of severe irritability/anger in children is that this phenomenon is widely believed to account for significant misdiagnosis of children as having bipolar disorder. This is particularly true in the U.S., where rates of bipolar disorder diagnoses in children increased by as much as 4000% between 1994 and 2003 6. The growing incidence of pediatric bipolar disorder appeared to be due to diagnostic errors or changing diagnostic conventions, since risk factors for the disorder had not changed and international data did not show a similar increase 7. The view that mania and hypomania could present as irritability among children appeared to underlie this changing diagnostic pattern 4, 7. Notably, a large majority of the children diagnosed with bipolar disorder based on this interpretation of irritability would have also met the diagnostic requirements for oppositional defiant disorder (ODD) 4. Though generally grouped with conduct disorder and other disorders characterized by disruptive behavior, ODD is a disorder of emotional dysregulation 8, partially defined by affective symptoms of irritability and anger 5, 9 and sharing significant comorbidity and continuity with mood and anxiety disorders 10, 11. Thus, increasing rates of bipolar disorder diagnosis in children could reflect: a) diagnostic confusion regarding the presentation of bipolar disorder among children; and b) the presence of more severe symptoms of emotional dysregulation in children more properly considered as having ODD. Seeking to clarify the relationship between irritability and bipolar disorder, researchers at the U.S. National Institute of Mental Health began investigating “severe mood dysregulation” (SMD), a syndrome characterized by chronic abnormal levels of anger or sadness, hyperarousal evident in insomnia or agitation, and heightened verbal or physical reactivity 12. SMD and severe irritability/anger in childhood were found to predict anxiety and depressive disorders, but not bipolar disorders, in adolescence and adulthood (13-15). At the same time, researchers have examined the “irritability dimension” of ODD, which typically includes often losing one's temper, being touchy, and being chronically or frequently angry, but not the hyperarousal symptoms of SMD. It has long been established that a significant proportion of children with ODD follow a developmental pathway leading to more serious antisocial behaviours characteristic of conduct disorder 16. However, children with these irritable/angry symptoms of ODD appear to follow a different course, with outcomes more commonly including later depression and anxiety (17-19), as well as peer victimization 20 and greater treatment resistance and functional impairment following treatment 21. Overall, severe irritability/anger appears to be a clinically significant feature and predictor of outcomes across development, from early childhood 22, 23 through adulthood 15, with similar findings in girls and boys. Further, irritability/anger may have distinct genetic underpinnings from resistant behaviours and conduct problems 24. Clearly, this is an area deserving careful clinical attention. During the period of increasing diagnostic rates of childhood bipolar disorder in the U.S., there was also an increasing tendency to use medications appropriate for adult bipolar disorder in an attempt to a