Introduction
In the last 20 years there has been a marked rise in the number of children and adolescents receiving the diagnosis of bipolar disorder (BD) – a mood disorder that, classically, involves cycling between episodes of elevated mood and episodes of low mood ( Arch. Gen. Psychiatry 2207;64:1032-9 ). The increase in diagnosis is partly explained by the inclusion of children with chronic irritability being diagnosed with BD. This has led to concern about the subsequent use of approved second-generation antipsychotics for chronically irritable children, with the resultant side effects.
A new diagnosis called disruptive mood dysregulation disorder (DMDD) was introduced into the DSM-5 to describe these chronically irritable children and, in part, to reduce the number of children receiving a bipolar diagnosis. So, how does one know whether a child has BD, DMDD, or something else? The two brief cases that follow distinguish the difference between BD and DMDD.
Case 1 summary
Joseph is a 15-year-old boy with a history of childhood depression. About 1 year ago, he began to appear more irritable and anxious. Despite his parents’ prohibition, he was going out at night and was intoxicated on several occasions when he came home – something he had never done before. After about 2 weeks of this, he began going to bed at midnight, but would be up again by 4 a.m. talking to himself, playing music, or exercising. He was hanging out with a different crowd. He began to talk about the possibility of becoming part of a motorcycle gang – at some point perhaps the leader of Hells Angels. Slowly, this resolved. However, these symptoms recurred about 1 month ago with progressive worsening, again, and 2 days ago he stopped sleeping at all. He has been locking himself in his room, talking rapidly and excessively about motorcycles, complaining that he “just needed to get his thoughts together.” He was very distractible and was not eating. His mother called his primary care clinician who advised her to bring him to the ED, which she could do only by police because he refused to leave the home, complaining of the “noises” outside.
Case 1 discussion
Joseph most likely has bipolar I disorder, although a substance-induced mania will have to be ruled out. His symptoms are classic for what we think of as “narrow phenotypic” mania – elated and irritable mood, grandiosity, flight of ideas, decreased need for sleep, hypertalkativeness, increase in goal-directed activity, severe distractibility, and excessive involvement in activities that are likely to have painful consequences. These episodes are a clear change from baseline. Here, Joseph has been previously depressed, but never had symptoms like this that came, went, and then returned. If these manic symptoms continue for 1 week or longer, or are so severe as to require him to be hospitalized, these are a manic episode, which, essentially, makes the diagnosis of bipolar I disorder. Most clinicians have seen mania in late adolescence and early adulthood and can distinguish when these episodes occur in childhood. There is less ambiguity about this diagnosis when it occurs with frank mania.
Case 2 summary
Henry is a 12-year-old boy. His parents say that he’s been difficult since he was “in the womb.” Starting at about the age of 4 years, they started to notice that he would frequently become moody – lasting almost all day in a way that was noticed by everyone. He remains almost constantly irritable. He responds extremely to negative emotional stimuli, like when he got so upset about striking out at a Little League game last year that he had a 15-minute temper outburst that couldn’t be stopped. When his father removed him from the field to the car, he kicked out a window. These types of events are not uncommon, occurring four to five times per week, and are associated with verbal and physical aggression. There have been no symptom-free periods since age 4 years. There have been no clear episodes, and nothing that could be described as elation.
Case 2 discussion
Henry would very likely meet the criteria for the DSM-5 diagnosis of disruptive mood dysregulation disorder. DMDD requires that there be severe and recurrent temper outbursts that can be verbal or physical and are grossly out of proportion to the situation, happening at least three times a week for the past year. In between these outbursts, the child’s mood is angry or irritable, most of the day, nearly every day with no time longer than 3 months in the last year without symptoms. There cannot be symptoms of mania or hypomania. DMDD should be distinguished from oppositional-defiant disorder (ODD), which cannot be diagnosed concurrently. ODD has similar characteristics, but the temper outbursts are not as severe, frequent, or chronic. The mood symptoms in DMDD predominate, while oppositionality predominates in ODD. Note the chronicity of irritable mood in DMDD. This is the distinguishing characteristic of the disorder – chronic, nonepisodic irritability.
General discussion
The distinction between BD and DMDD does matter, but it is sometimes quite hard to draw a clear line – even for the experts. It can be easy to be frustrated with yourself as a clinician when you’re unable to come to a clear decision about the diagnosis. With mood disorders in children, however, it’s important not to attribute the field’s lack of clarity to your own lack of knowledge. In these difficult cases, it’s highly likely that even the experts would disagree. Making the distinction between bipolar disorder and DMDD becomes even more complex in the situation of “other specified bipolar and related disorders,” which allows for short or subsyndromal hypomanic episodes with major depression, hypomania without depression, or short-duration cyclothymia. These cases, formerly called “bipolar, not otherwise specified,” are more likely to progress to adult bipolar disorder I or II. DMDD, on the other hand, is more likely to progress to adult depression ( Biol. Psychiatry 2006;60:991-7 ).
Why does the distinction matter? Because the treatment for bipolar disorder is likely to involve one of the traditional mood stabilizers or the second-generation antipsychotics that are Food and Drug Administration–approved for bipolar disorder along with family education and cognitive-behavioral therapy. However, there is no evidence at this time that the management of DMDD should consist of these same treatments. In fact, a trial of lithium for DMDD (actually, its research predecessor severe mood dysregulation) was negative ( J. Child. Adolesc. Psychopharmacol. 2009;19:61-73 ). While we are still working out how to help children with DMDD, the current trials being done are examining the use of antidepressants and psychostimulants (either serially or in combination) along with family-based interventions similar to those used for ODD. These are tough cases, and frequently a consult with a child psychiatrist or psychologist will be helpful.
Dr. Althoff is an associate professor of psychiatry, psychology, and pediatrics at the University of Vermont, Burlington. He is director of the division of behavioral genetics and conducts research on the development of self-regulation in children. Dr. Althoff has received grants/research support from the National Institute of Mental Health, the National Institute of General Medical Sciences, the Research Center for Children, Youth, and Families, and the Klingenstein Third Generation Foundation, and honoraria from the Oakstone General Publishing for CME presentations. E-mail him at pdnews@frontlinemedcom.com .
