disruptive mood dysregulation disorders

**DSM-5 diagnostic criteria (high-yield):** - Severe recurrent temper outbursts (verbal rage and/or physical aggression toward people or property) grossly out of proportion in intensity or duration to the situation and inconsistent with developmental level. - Frequency: ≥3 times per week. - Mood between outbursts: persistently irritable or angry most of the day, nearly every day, observable by others (parents, teachers, peers). - Duration: symptoms present ≥12 months, with no symptom-free period lasting ≥3 consecutive months. - Setting: present in ≥2 of 3 settings (home, school, with peers), and severe in at least one. - Age: diagnosis should not be made before age 6 or after age 18. Age of onset is before age 10. - Never a distinct manic or hypomanic episode lasting >1 day (this is the key distinction from bipolar disorder).

**Exclusions / cannot coexist with:** - Oppositional defiant disorder (ODD), intermittent explosive disorder, or bipolar disorder. If criteria for both DMDD and ODD are met, give only the DMDD diagnosis. - Can coexist with major depressive disorder, ADHD, conduct disorder, and substance use disorders. - Symptoms must not be attributable to substances, another medical or neurologic condition, or occur only during an episode of MDD or another psychiatric disorder (e.g., autism spectrum disorder, PTSD, separation anxiety).

**Pathophysiology / epidemiology:** - Etiology is not fully defined. Research implicates deficits in emotion regulation, frustration tolerance, and threat/reward processing (amygdala and prefrontal circuitry dysfunction). - Prevalence is about 2–5% in children; more common in males and in school-age children, and declines in adolescence. - It is associated with irritability as a core dimension (chronic, non-episodic).

**Why it exists:** - In the 1990s–2000s, pediatric bipolar disorder was diagnosed more often, including for children with chronic non-episodic irritability. DMDD was added to DSM-5 (2013) under Depressive Disorders to reflect that these children are not at high risk for bipolar disorder.

**Natural history:** - Longitudinal studies show that chronic irritability predicts later unipolar depressive and anxiety disorders, not bipolar disorder.

**Management:** - First line is psychosocial treatment: parent management training (PMT) and cognitive behavioral therapy (CBT) for the child, emphasizing emotion regulation and frustration tolerance. - Pharmacotherapy is adjunctive and based on limited evidence. Options include stimulants if comorbid ADHD (may reduce irritability), SSRIs if comorbid anxiety or depression, and atypical antipsychotics (e.g., risperidone, aripiprazole) for severe aggression, with metabolic monitoring. - There is no FDA-approved medication specifically for DMDD.

**Board differentiators:** - **Bipolar disorder:** episodic mood elevation with decreased need for sleep, grandiosity, and distractibility lasting days. DMDD is chronic and non-episodic. - **ODD:** pattern of angry/irritable mood, argumentative/defiant behavior, and vindictiveness, without the severe, frequent outbursts of DMDD. DMDD takes precedence if both are met. - **Intermittent explosive disorder:** discrete impulsive aggressive outbursts, but mood between outbursts is normal. - **Conduct disorder:** violation of others' rights and societal norms (e.g., theft, cruelty, fire-setting) rather than mood-driven outbursts. - **MDD:** in children, irritability can be the mood symptom, but the pattern is episodic and accompanied by neurovegetative symptoms and anhedonia.

**Classic vignette:** An 8-year-old boy has had daily irritability and angry mood for over a year, with explosive tantrums 4–5 times a week at home and school, such as screaming and throwing objects over minor frustrations. There are no discrete episodes of elevated mood or decreased need for sleep. The diagnosis is DMDD.