Irritability is the most common reason children are brought for psychiatric evaluation. It is a diagnostic criterion or associated symptom for multiple diagnoses listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).
Over the past 20 years, much has been learned about brain and behavior mechanisms that involve irritability, but published reports are often marred by excessive jargon.
To help clinicians overcome this problem, so they can understand this important research and begin to consider how to apply it to their patients, Daniel P. Dickstein, MD, FAAP, chief of McLean Hospital’s Nancy and Richard Simches Division of Child and Adolescent Psychiatry and director of the PediMIND Program at McLean Hospital, and colleagues published their review in Child and Adolescent Psychiatric Clinics of North America.
Tools of the Trade
The paper begins with a clear discussion of the various magnetic resonance imaging (MRI) techniques used to study brain structure and function in people with mental health problems.
It also explains how computerized games can be used to assess cognitive and emotional processes related to irritability:
- Cognitive flexibility (the ability to adapt to changing rewards and punishments)
- Reward processing/frustrative non-reward (the response stemming from blocked goal attainment)
- Response inhibition (the ability to stop a dominant, natural reaction)
- Emotional face processing (the ability to identify what emotion someone else’s face is showing)
The article then reviews what’s known about irritability in four major psychiatric disorders.
Bipolar Disorder (BD)
Youth with bipolar disorder (BD) show dysfunction in the prefrontal cortex striatal-amygdala circuit, which mediates all four processes listed above. These deficits have been observed during euthymia (normal mood), so they aren’t byproducts of mania itself, and they persist when individuals with prospectively documented childhood-onset BD become adults.
The deficits have also been found in youth at risk of BD because they have first-degree relatives with the disorder. That suggests these may be trait deficits distinct from those seen in children with chronic irritability who meet research criteria for severe mood dysregulation.