ADHD and persistent tic disorder are highly comorbid in children, and this relationship may be due to unique underlying neural structures. When both disorders are present, symptoms tend to be more severe, but it is primarily the ADHD that contributes to the behavioral dysfunction experienced by these children.
- Many children with ADHD also have persistent tic disorder.
- Children with only ADHD or PTD have distinct symptoms.
- Children with both ADHD and PTD have more severe symptoms, but ADHD is the main driver of behavioral dysfunction.
Neurodevelopmental disorders are often difficult to manage and can have negative effects on children’s cognitive and behavioral functioning. About 6% of the pediatric population has attention-deficit/hyperactivity disorder (ADHD). Persistent tic disorder (PTD) is a less common childhood disorder, but approximately 20% of children with ADHD also meet the criteria for PTD. Because these two conditions are highly comorbid, their symptoms can interact and influence a child’s behavior and outcomes.
Studying the Neural Dynamics of ADHD and PTD
A study published in Biological Psychiatry sought to understand the neural dynamics of ADHD and PTD and parse their unique mechanisms leading to behavioral dysfunction. Electroencephalogram (EEG) recordings were performed and analyzed for connectivity patterns in a sample consisting of children with ADHD, PTD, or both ADHD and PTD, as well as a group of healthy controls.
Participants underwent diagnostic interviews and behavioral assessments, followed by electroencephalography testing. Children with ADHD had significantly higher problem scores on the Child Behavior Checklist and Behavior Rating Inventory of Executive Function, while children with PTD had greater thought and internalizing problems. Children with both ADHD and PTD had more severe symptoms on these scales than those with PTD only and children with neither condition.
EEG Connectivity Analysis Results
EEG connectivity analysis showed lower information flow among occipital–frontal and intraoccipital connections in children with ADHD. Children without an ADHD or PTD diagnosis had higher connectivity than all other groups.
In the behavioral, cognitive, and neural measures compared in this study, ADHD diagnosis appears to be the major driver of dysfunction. Most differences in brain connectivity measures were related to ADHD, and PTD had an additive effect on behavioral outcomes.
Understanding Behavioral Functions in Children With ADHD and PTD
Identifying distinct patterns of neural connectivity correlating with ADHD and PTD diagnosis provides insight into how each contributes to behavioral functions. As children with these disorders tend to struggle academically and socially, understanding transdiagnostic factors leading to particular behavioral profiles can provide information for future studies to develop strategies for intervention.
Jurgiel, J., Miyakoshi, M., Dillon, A., Piacentini, J., & Loo, S. K. (2022). Additive and Interactive Effects of Attention-Deficit/Hyperactivity Disorder and Tic Disorder on Brain Connectivity. Biol Psychiatry Cogn Neurosci Neuroimaging. https://doi.org/10.1016/j.bpsc.2022.10.003