I can't speak to this myself. Hopefully there will be some other members who will. In the meantime, here are links to some articles, from PsychCentral's archives, on disruptive mood dysregulation disorder the first 2 by our host Dr. John Grohol, Psy.D.:

What is Disruptive Mood Dysregulation Disorder?

Symptoms of Disruptive Mood Dysregulation Disorder

Disruptive Mood Dysregulation Disorder: A Primer | Psych Central Professional