Neural Findings in Pediatric Irritability

Irritability has been conceptualized as a clinical phenomenon that cuts across various psychiatric disorders. Moreover, it is one of the most common reasons that children and adolescents present for mental health treatment. Despite the high prevalence and impairment associated with irritability, until recently, relatively little was known about the brain mechanisms underlying it. Understanding more about the neural mechanisms associated with irritability will likely enhance treatment development. In this chapter, the authors synthesize research that has characterized aspects of irritability in children and adolescents who are typically developing and in those with psychiatric disorders, including severe mood dysregulation (SMD), disruptive mood dysregulation disorder (DMDD), bipolar disorder, and disruptive behavior disorders, as well as attention deficit/hyperactivity disorder and autism, and they suggest future directions for research in this area.

Proper Emotion Recognition, Dysfunctional Emotion Regulation

Objective: A considerable number of adolescents exhibit severe self-regulation deficits in affect and behavior, which are referred to as affective dysregulation (AD). AD may be conceptualized as a dimensional trait that, in its extreme form, resembles the diagnostic categories of severe mood dysregulation (SMD) or disruptive mood dysregulation disorder (DMDD). Assuming a shared pathway of psychopathology in AD and SMD, similar underlying dysfunctional mechanisms in emotion processing, particularly emotion recognition (RECOG) and regulation (REGUL), may be postulated. Method: Adolescent inpatients with AD (CAD, N = 35), without AD (CCG, N = 28), and nonclinical controls (NCG; N = 28) were administered a morphed facial recognition task (RECOG). REGUL abilities, levels of irritability as well as depressive symptoms were also assessed. Results: We found no significant group differences in accuracy and thresholds for RECOG abilities. Patients with AD reported more dysfunctional REGUL strategies than did CCG and NCG. Both depression and AD, but not irritability, influenced the overall degree of maladaptive REGUL. Conclusion: The broad phenotype of AD does not involve the deficits in RECOG reported for adolescents with a narrow phenotype (SMD); regarding REGUL strategies, AD seems to be associated with specific impairments.

Disruptive mood dysregulation disorder, severe mood dysregulation and chronic irritability in youth at high familial risk of bipolar disorder

Objective: Disruptive mood dysregulation disorder is a newly proposed childhood disorder included in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition to describe children ⩽18 years of age with chronic irritability/temper outbursts. This study aimed to examine the prevalence of disruptive mood dysregulation disorder, severe mood dysregulation and chronic irritability in an Australian study of young people at increased familial risk of developing bipolar disorder (‘HR’ group) and controls (‘CON’ group). Methods: A total of 242 12- to 30-year-old HR or CON subjects were administered the severe mood dysregulation module. Of these, 42 were aged ⩽18 years at the time of assessment, with 29 subjects in the HR group and 13 in the CON group. Results: No subjects ⩽18 years – in either group – fulfilled current or lifetime criteria for disruptive mood dysregulation disorder or severe mood dysregulation, the precursor to disruptive mood dysregulation disorder. Similarly, no subjects in either group endorsed the severe mood dysregulation/disruptive mood dysregulation disorder criteria for irritable mood or marked excessive reactivity. One HR participant endorsed three severe mood dysregulation criteria (distractibility, physical restlessness and intrusiveness), while none of the comparison subjects endorsed any criteria. Exploratory studies of the broader 12- to 30-year-old sample similarly found no subjects with severe mood dysregulation/disruptive mood dysregulation disorder in either the HR or CON group and no increased rates of chronic irritability, although significantly more HR subjects reported at least one severe mood dysregulation/disruptive mood dysregulation disorder criterion (likelihood ratio = 6.17; p = 0.013); most of the reported criteria were severe mood dysregulation ‘chronic hyper-arousal’ symptoms. Conclusion: This study comprises one of the few non-US reports on the prevalence of disruptive mood dysregulation disorder and severe mood dysregulation and is the first non-US study of the prevalence of these conditions in a high-risk bipolar disorder sample. The failure to replicate the finding of higher rates of disruptive mood dysregulation disorder and chronic irritability in high-risk offspring suggests that these are not robust precursors of bipolar disorder.