Children with ADHD who also experience severe emotional outbursts show distinct differences in brain structure and connectivity, according to a new study published in psychiatry.
Attention-deficit/hyperactivity disorder (ADHD) is widely known for its symptoms of inattention and hyperactivity, but many children also suffer from intense emotional reactions such as tantrums, anger, and restlessness. Although these emotional problems are not part of the official diagnostic criteria for ADHD, they may be one of the most disabling aspects of ADHD. Previous brain imaging studies have struggled to identify consistent neural markers of ADHD. One reason for this is that these emotional symptoms have often been overlooked.
Researchers in the new study, led by Amy Crane Roy of Fordham University, wanted to understand whether the emotional and behavioral difficulties of ADHD arise from the same or different brain mechanisms. They were particularly interested in children who experience “disordered emotional outbursts” (IEOs), defined as severe verbal or physical outbursts that occur several times a week, are developmentally inappropriate and interfere with daily life.
To investigate this, the research team recruited 123 children (94 males) between the ages of 5 and 9.9 years. The sample included 47 children with both ADHD and IEO, 39 children with ADHD but without outbursts, and 37 neurotypical children. Parents completed detailed questionnaires about their children’s behavior and emotions, and the children underwent structural and functional brain MRI scans.
Roy’s team first analyzed behavioral data using statistical methods to identify aspects of underlying behavior. They extracted four main behavioral factors: externalizing behaviors (e.g., aggression, anger, hyperactivity), emotion dysregulation (e.g., positive and negative mood instability), internalizing behaviors (e.g., anxiety), and impulsivity/impulsivity. The most notable difference was in the externalizing behavior factor, which was significantly higher in children with both ADHD and emotional outbursts than in the other two groups.
The researchers then used a machine learning technique called latent Dirichlet allocation (LDA) to examine the structure of the children’s brains. This data-driven approach allowed us to uncover hidden patterns in cortical thickness across the brain without relying on preconceptions. They found that children with ADHD and emotional outbursts had greater cortical thickness in an area of the brain called the left dorsolateral prefrontal cortex (DLPFC) compared to neurotypical children. This area is deeply involved in self-control, attention, and emotional regulation. Furthermore, the thickness of this region was directly associated with higher scores on the “externalizing behavior” factor.
To understand how this structural difference affects brain function, the researchers used the DLPFC as a “seed” to examine how communication with other parts of the brain differed between the groups during resting-state fMRI scans.
Roy’s team found that compared to neurotypical children, both ADHD groups had weaker communication between the DLPFC and parts of the brain’s default mode network involved in introspection and daydreaming.
However, when the two ADHD groups were compared with each other, crucial differences emerged. Children with ADHD and emotional outbursts showed significantly weaker connections between the DLPFC and visual, dorsal attention, and salience networks compared to ADHD children without outbursts. This particular miscommunication, the inability of the brain’s control centers to properly interact with areas that process visual and emotional stimuli, suggests a distinct neural signature of severe emotional dysregulation in ADHD.
As the authors explain, combining behavioral, structural, and functional data reveals unique neural signatures associated with behavioral and emotional dysregulation. Their findings suggest that severe emotional outbursts in ADHD may reflect distinct biologically based brain differences rather than just a behavioral problem, supporting the idea that emotional dysregulation should be considered a core component of the ADHD diagnosis for some children.
However, this study has limitations. Because this is cross-sectional, we cannot determine whether these brain differences cause emotional outbursts or whether they are due to the passage of time. Additionally, the behavioral factors were based solely on parent questionnaires, which may introduce bias. Finally, given the young age of the participants, the fMRI scan lasted only 6 minutes. A longer scan would have improved the reliability of the functional connectivity data.
The study, “Mapping potential neuroanatomical substrates of behavioral and emotional dysregulation in ADHD,” was authored by Shinwon Park, Margaret Benda, Anthony Mekhanik, Michael P. Milham, Seok Jun Hon, and Amy Krain Roy.
