Wednesday, April 15, 2015

Disruptive Mood Dysregulation Disorder Revisited

In the brief history of this blog, the post where I shared my thoughts on DSM-5's disruptive mood dysregulation disorder (DMDD) has gotten by far the most pageviews. It's been almost two years since I wrote that post, and I would like to revisit DMDD with some updated thoughts on this diagnosis.

As you may recall, DMDD sprang out of a desire to have a diagnosis other than "bipolar disorder" to describe children who are chronically irritable and have explosive tantrums. Almost all of the children with DMDD also meet the criteria for oppositional defiant disorder (ODD) and are at higher risk of developing depression but not mania. The NIMH researcher Ellen Leibenluft, whose work on severe mood dysregulation (SMD) strongly influenced DMDD's creation, had commented in the past that she was not 100% sure that DMDD was a good idea.

In the last few years, I have only seen a handful of children who met the criteria for DMDD. Here is what I noticed in my own practice:
  • One boy was being raised by a single mother who worked full time, so his grandparents were very involved in childrearing. The mother tried to set rules, but the grandparents were much more permissive, and whenever the mother tired to enforce her rules, explosive tantrums resulted.
  • Another boy was very violent toward his mother on an almost daily basis. His father was home but did not intervene, while the mother had anxiety and literally appeared fearful of her son during their visits with me. When he hit her, she would tell him verbally that it was wrong, but did not do anything else (like using a time-out) to try to change his behaviors.
  • There was a girl (who I'd written about previously) whose mother was very emotionally distant and pulled away further every time the girl acted out because the mother was reminded of her own emotionally intense mother. This distancing seemed to lead to the daughter becoming even more irritable.
  • And then there was a boy who was extremely aggressive at home, constantly fighting with his 3 siblings. The household was very chaotic, with parents still married but frequently arguing with each other. Both parents often resorted to spankings, which did not seem to decrease the boy's aggression or irritability.
Certainly, correlation between the parental characteristics and the children's behaviors does not tell us about causation. It is very stressful raising irritable, explosive children, and the children described above definitely had intense, strong-willed temperaments. My intuition is that it's an interactive process where both parental and child characteristics trigger maladaptive behaviors in each other that escalate over time. But are these families typical of cases of DMDD? I searched Pubmed for "disruptive mood dysregulation disorder" and found 20 papers published in the last 2 years (out of 29 total).

Of the 20, most were reviews/commentary, and only 6 papers were original research. One was a brain imaging study looking at "neural mechanisms of frustration in chronically irritable children." Another examined the prevalence of SMD 2 and 4 years out from initial diagnosis, and found that 40% still met full criteria at 4 years, but a significant number not meeting the criteria were still moderately impaired. Another study from Duke's developmental epidemiology program used a large database to examine the adult outcomes of those who would have met DMDD criteria as children and found higher adult rates of depression, anxiety, adverse health outcomes, impoverishment, police contact, and lower educational attainment.

To my pleasant surprise, there were actually several papers that included data on family characteristics of children with DMDD. The first was a cross-sectional study of a community sample of 6 year-old children, which found that 8.2% of them met DMDD criteria based on a structured interview of parents. Impressively, the study examined 6 domains ("demographics; child psychopathology, functioning, and temperament; parental psychopathology; and the psychosocial environment") for correlates of DMDD. The parents were also interviewed about what things had been like when their children were 3 years old, and here's what the researchers found:
The age 3 years predictors of DMDD at age 6 years included child attention deficit hyperactivity disorder, oppositional defiant disorder, the Child Behavior Checklist - Dysregulation Profile, poorer peer functioning, child temperament (higher child surgency and negative emotional intensity and lower effortful control), parental lifetime substance use disorder and higher parental hostility.
The second study was a prospective one that "followed 317 high-risk children with early externalizing problems from school entry (ages 5-7) to late adolescence (ages 17-19)." The children sorted into 3 groups by the time they were adolescents: one group with conduct/criminal problems and anger, one group with mood dysregulation, and one group with a low level of symptoms. The authors found that generally, those who were more overtly aggressive as children tended to have conduct problems as adolescents, while more emotionally dysregulated children had more mood dysregulation in adolescence. The key finding:
For children with early emotion dysregulation, however, increased risk for mood dysregulation characterized by anger, dysphoric mood, and suicidality - possibly indicative of disruptive mood dysregulation disorder - emerges only in the presence of low parental warmth and/or peer rejection during middle childhood.
Another study (with 13! authors) was published in a much more prestigious journal than the previous 2 papers, and to me it was the least enlightening. The study examined the risk of DMDD in offspring of parents with bipolar disorder and found a much higher risk of DMDD (odds ratio = 5.4 "when controlling for demographic variables and comorbid parental diagnoses") compared to offspring of control parents. Given what those two other studies found, I'm not surprised that parents with bipolar disorder, one of the most severe psychiatric illnesses, would have children at risk of DMDD.

One last noteworthy paper that turned up in my Pubmed search is a recent article on whether DMDD should be included in ICD-11. The International Classification of Diseases is the World Health Organization's standard system for classifying every health problem imaginable, and the 11th revision is due in 2017. Even in the U.S., the ICD diagnostic codes are the standard for coding and billing purposes, and each DSM diagnosis is mapped to a corresponding ICD code. In this paper, the authors, who were members of a task group convened by the WHO to provide recommendations on the classification of disruptive behavior disorders, wrote:
The task group has recommended that WHO not accept DMDD as a diagnostic category in ICD-11, but rather approach the issue in an alternative, more conservative and more scientifically justifiable way. Specifically, the group has proposed that ICD-11 include a specifier to indicate whether or not the presentation of ODD includes chronic irritability and anger. We believe this option provides the most parsimonious basis for identifying and appropriately treating children with this maladaptive form of emotional dysregulation.
In my previous post on DMDD, I thought that it was overall a positive step away from the rampant over-diagnosis of pediatric bipolar disorder. But I did not end up using it; I was not about to diagnose those children with bipolar disorder in the first place. Thus, I find myself agreeing with the WHO task group. With ODD, the standard first line treatments are interventions that help parents better manage their children's behaviors and/or improve the parent-child relationship. I still worry about drug companies trying to market a medication for DMDD that supposedly targets a problem in the brain of the child. Thankfully, at least Abilify hasn't been approved yet for treating DMDD and hopefully never will, having gone off-patent this year.