Top-Down Dysregulation-From ADHD to Emotional Instability

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Attention-deficit/hyperactivity disorder (ADHD) is traditionally linked to deficient cognitive top-down executive control, explaining only a modest part of its phenotype.
• Emotional dysregulation is increasingly recognized as a significant factor in ADHD.
• Existing models do not fully capture the interplay between cognitive and emotional deficits in ADHD.

Purpose of the Study:

• To propose a unified model of top-down dysregulation that spans from non-emotional ('cool') executive functions to emotional regulation ('hot') processes.
• To integrate ADHD, emotional traits in ADHD, and personality disorders like borderline and antisocial personality disorder within this gradient framework.
• To explore the neuroanatomical and neurochemical underpinnings of this proposed gradient.

Main Methods:

• Conceptual model development integrating existing research on executive functions, emotional regulation, and neurobiology.
• Neuroanatomical mapping of 'cool' executive functions to prefrontal cortex (dlPFC, cACC) and 'hot' functions to orbitofrontal cortex (rACC).
• Examination of basal ganglia and dopamine system involvement in processing exteroceptive (cool) versus interoceptive (hot) information.

Main Results:

• A gradient model of top-down dysregulation is proposed, encompassing both cognitive and emotional control.
• ADHD is positioned primarily towards the 'cool' end, while personality disorders are closer to the 'hot' end, with emotional ADHD subtypes in between.
• Distinct neuroanatomical circuits (prefrontal vs. orbitofrontal) and processing systems (exteroceptive vs. interoceptive) are associated with 'cool' and 'hot' functions.

Conclusions:

• The proposed gradient framework offers a more comprehensive explanation for the phenotypic variance in ADHD, including emotional aspects.
• This model provides a potential neurobiological basis for understanding the relationship between ADHD and emotional dysregulation disorders.
• The framework may help integrate seemingly distinct conditions into a related cluster of mental health challenges.