Irritable mood, a common and impairing symptom in psychopathology, has been proposed to underlie the developmental link between oppositional problems in youth and depression in adulthood. Here, we examined the neural correlates of adolescent irritability in IMAGEN, a sample of 2024 14-year-adolescents from five European countries.
The Development and Well-Being Assessment (DAWBA) was used to assess attention-deficit/hyperactivity disorder (ADHD), major depressive disorder (MDD), oppositional defiant disorder (ODD), and generalized anxiety (GA). Three items from the DAWBA, selected as close matches to the Affective Reactivity Index, were used to assess irritability. Structural MRI was examined using whole brain Voxel Based Morphometry analysis and functional MRI was examined during a stop signal task of inhibitory control. Imaging data were included in structural equation models (SEM) to examine the direct and indirect associations between irritable mood and comorbid DSM diagnoses.
Whole brain voxel wise analysis showed that adolescent irritable mood was associated with less grey matter volume and less neural activation underlying inhibitory control in frontal and temporal cortical areas (cluster-correction at p<0.05). SEM models suggested that part of the observed smaller GMV is exclusively driven by irritability separate from direct relationships between GA (or ADHD, MDD, ODD) and grey matter volume.
This study identifies adolescent irritability as an independent construct and points to a neurobiological correlate to irritability that is an important contributing feature to many psychopathological disorders.

Copyright © 2020. Published by Elsevier Inc.