The second manifestation of severe irritability consists of chronic, persistently irritable or angry mood that is present between the severe temper outbursts. This irritable or angry mood must be characteristic of the child, being present most of the day, nearly every day, and noticeable by others in the child’s environment (Criterion D).
The clinical presentation of disruptive mood dysregulation disorder must be carefully distinguished from presentations of other, related conditions, particularly pediatric bi- polar disorder. In fact, disruptive mood dysregulation disorder was added to DSM-S to address the considerable concern about the appropriate classification and treatment of children who present with chronic, persistent irritability relative to children who present with classic (i.e., episodic) bipolar disorder.
Some researchers view severe, non-episodic irritability as characteristic of bipolar dis- order in children, although both DSM-IV and DSM-S require that both children and adults have distinct episodes of mania or hypomania to qualify for the diagnosis of bipolar I dis- order. During the latter decades of the 20th century, this contention by researchers that severe, nonepisodic irritability is a manifestation of pediatric mania coincided with an up- surge in the rates at which clinicians assigned the diagnosis of bipolar disorder to their pediatric patients. This sharp increase in rates appears to be attributable to clinicians com- bining at least two clinical presentations into a single category. That is, both classic, epi- sodic presentations of mania and non-episodic presentations of severe irritability have been labeled as bipolar disorder in children. In DSM-5, the term bipolar disorder is explicitly reserved for episodic presentations of bipolar symptoms. DSM-IV did not include a diagno- sis designed to capture youths whose hallmark symptoms consisted of very severe, non- episodic irritability, whereas DSM-S, with the inclusion of disruptive mood dysregulation disorder, provides a distinct category for such presentations.
Disruptive mood dysregulation disorder is common among children presenting to pedi- atric mental health clinics. Prevalence estimates of the disorder in the community are un- clear. Based on rates of chronic and severe persistent irritability, which is the core feature of the disorder, the overall 6-month to 1-year period-prevalence of disruptive mood dys- regulation disorder among children and adolescents probably falls in the 2%—5% range.
However, rates are expected to be higher in males and school-age children than in females and adolescents.
The onset of disruptive mood dysregulation disorder must be before age 10 years, and the diagnosis should not be applied to children with a developmental age of less than 6 years.
It is unknown whether the condition presents only in this age-delimited fashion. Because the symptoms of disruptive mood dysregulation disorder are likely to change as children mature, use of the diagnosis should be restricted to age groups similar to those in which validity has been established (7—18 years). Approximately half of children with severe, chronic irritability will have a presentation that continues to meet criteria for the condition 1 year later. Rates of conversion from severe, nonepisodic irritability to bipolar disorder are very low. Instead, children with chronic irritability are at risk to develop unipolar de- pressive and/ or anxiety disorders in adulthood.
dysregulation disorder. Rates of bipolar disorder generally are very low prior to adoles- cence (<1%), with a steady increase into early adulthood (1%—2% prevalence). Disruptive mood dysregulation disorder is more common than bipolar disorder prior to adolescence, and symptoms of the condition generally become less common as children transition into adulthood.
Temperamental. Children with chronic irritability typically exhibit complicated psy- chiatric histories. In such children, a relatively extensive history of chronic irritability is common, typically manifesting before full criteria for the syndrome are met. Such predi- agnostic presentations may have qualified for a diagnosis of oppositional defiant disorder.