Cookie Preferences
By clicking, you agree to store cookies on your device to enhance navigation, analyze usage, and support marketing. More Info
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
January 6, 2025
Background:
Our understanding of Attention-deficit/hyperactivity disorder (ADHD) has grown and evolved considerably since it first appeared in the DSM-II as “Hyperkinetic Reaction of Childhood.” This study aimed to find the disorder’s placement within the modern psychopathology classification systems like the Hierarchical Taxonomy Of Psychopathology (HiTOP).
The HiTOP model aims to address limitations of traditional classification systems for mental illness, such as the DSM-5 and ICD-10, by organizing psychopathology according to evidence from research on observable patterns of mental health problems.. Is ADHD best categorized under externalizing conditions, neurodevelopmental disorders, or something else entirely? A recent study by Zheyue Peng, Kasey Stanton, Beatriz Dominguez-Alvarez, and Ashley L. Watts takes a closer look at this question using a symptom-focused approach.
The Study:
Traditionally, ADHD has been associated with externalizing behaviors, such as impulsivity and hyperactivity, or with neurodevelopmental traits, like cognitive delays. However, this study challenges the idea of placing ADHD into a single category. Instead, it maps ADHD symptoms across three major psychopathology spectra: externalizing, neurodevelopmental, and internalizing.
The findings reveal that ADHD symptoms don’t fit neatly into one box. For example, symptoms like impulsivity, poor school performance, and low perseverance were strongly associated with externalizing behaviors. On the other hand, cognitive disengagement (e.g., daydreaming, blank staring) and immaturity were closely linked to neurodevelopmental challenges. Interestingly, cognitive disengagement also showed ties to internalizing symptoms, such as anxiety or depression.
This research underscores the complexity of ADHD. Rather than treating ADHD as a single, unitary construct, the study advocates for a symptom-based approach to better understand and treat individuals. By acknowledging that ADHD symptoms relate to multiple psychopathology spectra, clinicians and researchers can move toward more nuanced classification systems and targeted interventions.
Conclusion:
Ultimately, this study highlights the need for modern systems to move beyond rigid categories and adopt a more flexible, symptom-focused framework for understanding ADHD’s place in psychopathology.
Peng, Z., Stanton, K., Dominguez-Alvarez, B., & Watts, A. L. (2024). Where does attention-deficit/hyperactivity disorder fit in the psychopathology hierarchy? A symptom-focused analysis. Journal of psychopathology and clinical science, 10.1037/abn0000966. Advance online publication. https://doi.org/10.1037/abn0000966
.png)
A recent study delved into the connection between fidgeting and cognitive performance in adults with Attention-Deficit/Hyperactivity Disorder. Recognizing that hyperactivity often manifests as fidgeting, the researchers sought to understand its role in attention and performance during cognitively demanding tasks. They designed a framework to quantify meaningful fidgeting variables using actigraphy devices.
(Note: Actigraphy is a non-invasive method of monitoring human rest/activity cycles. It involves the use of a small, wearable device called an actigraph or actimetry sensor, typically worn on the wrist, similar to a watch. The actigraph records movement data over extended periods, often days to weeks, to track sleep patterns, activity levels, and circadian rhythms. In this study, actigraphy devices were used to measure fidgeting by recording the participants' movements continuously during the cognitive task. This data provided objective, quantitative measures of fidgeting, allowing the researchers to analyze its relationship with attention and task performance.)
The study involved 70 adult participants aged 18-50, all diagnosed with ADHD. Participants underwent a thorough screening process, including clinical interviews and ADHD symptom ratings. The analysis revealed that fidgeting increased during correct trials, particularly in participants with consistent reaction times, suggesting that fidgeting helps sustain attention. Interestingly, fidgeting patterns varied between early and later trials, further highlighting its role in maintaining focus over time.
Additionally, a correlation analysis validated the relevance of the newly defined fidget variables with ADHD symptom severity. This finding suggests that fidgeting may act as a compensatory mechanism for individuals with ADHD, aiding in their ability to maintain attention during tasks requiring cognitive control.
This study provides valuable insights into the role of fidgeting in adults with ADHD, suggesting that it may help sustain attention during challenging cognitive tasks. By introducing and validating new fidget variables, the researchers hope to standardize future quantitative research in this area. Understanding the compensatory role of fidgeting can lead to better management strategies for ADHD, emphasizing the potential benefits of movement for maintaining focus.
Recent advancements in brain network analysis may help researchers better understand the dysfunctions of the complex neural networks associated with ADHD.
Controllability refers to the ability to steer the brain's activity from one state to another. In simpler terms, it’s about how different regions of the brain can influence and regulate each other to maintain normal functioning or respond to tasks and stimuli.
Researchers examined functional MRI (fMRI) data from 143 healthy individuals and 102 ADHD patients, they focused on a specific metric called the node controllability index (CA-scores). This metric helps quantify how different brain regions contribute to overall brain function.
The study revealed that individuals with ADHD exhibit significantly different CA-scores in various brain regions compared to healthy controls. These regions include:
These areas are crucial for processes such as decision-making, sensory processing, and attention.
This new study suggests that the controllability index might be a more effective tool in identifying brain regions that work differently in those with ADHD. This means that controllability could provide a clearer picture of the brain networks associated with ADHD.
Although ADHD still cannot be diagnosed with this type of imaging, studies such as this highlight the complexity of the disorder and provide new avenues for future research.
The Neuroeconomic Perspective
Neuroeconomics combines neuroscience, psychology, and economics to understand how people make decisions. Neuroeconomic studies suggest that brain regions responsible for evaluating risk and reward, including the prefrontal cortex and dopamine pathways, function differently in individuals with ADHD. These insights are crucial for developing more tailored interventions. For example, understanding how ADHD affects reward processing might inform strategies that help individuals resist impulsive choices or increase motivation for delayed rewards.
Understanding Decision-Making in ADHD
We know that decision-making is a sophisticated process involving various cognitive procedures. It’s not just about choosing between options but also about how to weigh risks, rewards, and potential future outcomes; Attention, motivation, and cognitive control are core to this process. For individuals with ADHD, however, this neural framework is affected by impairments in attention and impulse control, often resulting in “delay discounting”—the tendency to prefer smaller, immediate rewards over larger, delayed ones.
This propensity for impulsive decisions is more than a personal challenge; it has broader societal and economic implications. Previous studies have shown that these tendencies in ADHD can lead to issues in academics, work, finances, and personal relationships, emphasizing the need for targeted support and interventions.
Implications and Future Directions
This review highlights a need for continued research to bridge the gaps in understanding how ADHD-specific cognitive deficits influence decision-making. Viewing ADHD through a neuroeconomic lens clarifies how cognitive and neural differences affect decision-making, often leading to impulsive choices with economic and social impacts. This perspective opens doors to more effective interventions, improving decision-making for individuals with ADHD. Future policies informed by this approach could enhance support and reduce associated societal costs.
The FDA has approved a new once-daily pill called centanafadine (trade name SIMTRIYO®). Approved for adults and kids aged 6 and older (weighing at least 44 lbs / 20 kg), centanafadine is a new category of ADHD treatment that aims to give fast results with fewer of the downsides of traditional stimulants.
To understand why centanafadine is unique among medications for ADHD, it helps to look at how ADHD brain chemistry works:
Stimulants like Ritalin and Adderall work mainly in the dopamine system. Nonstimulants like atomoxetine, viloxazine, clonidine and guanfacine work mainly on the norepinephrine system. Centanafadine is the first drug in a new class called NDSRIs (Norepinephrine, Dopamine, and Serotonin Reuptake Inhibitors). We can describe its effects as follows:
What Did Clinical Trials Show?
The FDA approved centanafadine based on studies involving thousands of adults, teens, and children. Here are the key findings:
Centanafadine showed some improvement in ADHD symptoms within the very first week of taking it although a full effect takes about six weeks.
In adult trials, taking 200 mg or 400 mg daily led to significant improvements in real-world skills:
In trials with children (ages 6–12) and teens (ages 13–17), centanafadine significantly reduced core ADHD symptoms like hyperactivity, impulsivity, and lack of focus compared to a placebo.
About 30% to 40% of adults with ADHD also suffer from anxiety. Traditional stimulants can make anxiety worse. In a trial specifically designed for adults dealing with both ADHD and anxiety, centanafadine effectively treated ADHD symptoms without firing up their anxiety, which might be due to its serotonin boost.
Does Centanafadine have Side Effects?
While Centanafadine was well-tolerated by most people in studies, like any prescription medication, it comes with important safety guidelines.
Prescribing Warnings:
Common Side Effects:
Other Warnings:
The Bottom Line
Overall, centanafadine is a new step forward in how we treat ADHD. Because it acts differently in the brain than traditional treatments, patients who struggle with stimulant-related anxiety or side effects may find it useful to explore with their doctor.
A landmark nationwide study from South Korea has uncovered a significant link between prenatal exposure to air pollution — specifically nitrogen dioxide (NO2) — and an increased risk of ADHD in children.
While researchers have long suspected that air pollutants interfere with fetal brain development through inflammation and oxidative stress, this study is one of the largest and most comprehensive of its kind, following nearly 1.5 million births for up to 13 years.
Why South Korea?
South Korea provided a unique countrywide “laboratory” for this research due to two key infrastructure strengths:
Key Findings: The “Smoking Gun” of NO2
While the study looked at several pollutants, nitrogen dioxide — a byproduct of fossil fuel combustion in cars and power plants — emerged as the primary concern.
Pollutant
Association with ADHD Risk
Nitrogen Dioxide (NO2)
Strongest Link: Every 1-ppb (part-per-billion) increase in exposure linked to a 22% rise in risk.
Sulfur Dioxide (SO2)
Minimal Link: Only a slight 4% increase per ppb.
Ozone (O3) carbon monoxide (CO), & particulates
No significant association was found.
The scale of the NO2 risk is particularly striking. Over the typical range of exposure levels found in the study (an interquartile range of 13 ppb), the data suggest a threefold increase in ADHD risk for children in the highest-exposure groups compared to the lowest.
Accounting for Other Factors
To ensure the results weren’t skewed by other variables, the researchers controlled for a wide range of confounders including:
The authors emphasized the strong association between maternal nitrogen dioxide exposure and ADHD, while also noting the small but significant association with sulfur dioxide.
The Take-Away: A New Frontier for Public Health
Historically, air quality laws have been designed to protect our lungs and hearts. However, this study adds to a growing body of evidence suggesting that the brain is likewise vulnerable.
In a commentary on the findings, expert George Ayoub argued that “neurodevelopment should be explicitly considered” when governments perform cost-benefit analyses on air quality regulation. My view is a bit different. The association is intriguing but the study does not establish cause and effect. Many statistically significant environmental risk associations for neurodevelopmental disorders have disappeared after controlling for maternal risk for ADHD. I hope this research team will do those analyses if feasible.
Executive functions (EFs) are the cognitive control systems that allow people to pursue goals, make decisions, and adapt to changing circumstances. Researchers generally break them into three overlapping capacities: working memory (holding and manipulating information in mind), inhibitory control (suppressing impulses and filtering out distractions), and cognitive flexibility (switching between tasks or mental frameworks). Strong EFs in childhood predict academic achievement, social competence, and long-term mental health; weaknesses in these areas that go unaddressed can persist into adulthood, undermining school performance, career prospects, and well-being.
The Background:
Interest in training these skills has grown rapidly, but most research has been conducted in Western settings. China presents a distinctive context. Collectivist values make group-based programs culturally natural, and parental investment in academic outcomes is high. Both of these factors should, in theory, work in an intervention’s favor. At the same time, tightly scheduled school days (sessions typically capped at 30 minutes or less) constrain what is actually deliverable. A growing number of randomized controlled trials (RCTs) have tested EF interventions with Chinese children, but until now, no one has pulled that evidence together systematically.
The Study:
A new network meta-analysis did exactly that. The researchers screened RCTs involving Chinese children aged 3–12, including both typically developing children and those showing subclinical signs of ADHD or autism spectrum disorder (ASD), for instance, siblings of children with an ASD diagnosis. Children who already carried a formal neurodevelopmental diagnosis were excluded. Fifty-two trials covering nearly 3,000 children met the inclusion criteria. Interventions fell into four categories:
The headline finding is that three of the four intervention types produced statistically significant improvements across all three EF domains. The exception was the hybrid physical-cognitive program, which did not reach significance for inhibitory control. Positive results across the board might sound encouraging until you look at the actual effect sizes.
The Results:
The actual effects were negligible. Every significant result fell well below what methodologists define as a “small” effect (a standardized mean difference, or SMD, of 0.2). The largest effect size in the entire analysis was an SMD of 0.097 (less than half that threshold). The authors summarize the interventions’ effects as “modest,” but that is generous phrasing for numbers that, in practical terms, amount to very little. The analysis also showed signs of publication bias, meaning that studies with null or negative results may not have been published, potentially inflating even these modest figures.
The Take-Away:
It is important to note that these results don’t necessarily mean that this is the last word on EF training. The results apply specifically to Chinese children working within the time constraints of Chinese school schedules, and they exclude children with diagnosed ADHD, a population for whom cognitive interventions sometimes show larger effects. Generalizing beyond those boundaries is unwarranted.
What the findings do suggest is that structured EF programs, as currently implemented in Chinese educational settings, are not delivering meaningful real-world benefits. Statistical significance, it is worth remembering, is not the same as practical significance, and the gap between the two is sharp here.
_logo%201.svg)
