Identifying Novel Types of Irritability Using a Developmental Genetic Approach

Area of Science:

• Developmental Psychology
• Psychiatry
• Genetics

Background:

• Irritability is a common mental health concern, presenting diagnostic and treatment challenges.
• Conceptualizing irritability is complex, with potential links to neurodevelopmental and mood disorders.

Purpose of the Study:

• To investigate distinct irritability trajectories using a developmental approach.
• To test the hypothesis of neurodevelopmental/ADHD-like and depression/mood-like irritability types.

Main Methods:

• Analysis of a prospective U.K. population-based cohort (n=7,924) from childhood to adolescence.
• Identification of irritability trajectory classes using longitudinal data.
• Assessment of psychiatric diagnoses and polygenic risk scores (PRS) for ADHD and depression.

Main Results:

• Five irritability trajectories were identified: low, decreasing, increasing, late-childhood limited, and high-persistent.
• Early-onset high-persistent irritability associated with childhood ADHD and ADHD PRS.
• Adolescent-onset increasing irritability linked to adolescent depression and depression PRS.

Conclusions:

• Irritability's developmental context is crucial for conceptualization.
• Early-onset irritability may resemble ADHD, while later-onset forms align with depression.
• Findings inform nosology and treatment strategies for irritability.