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June 13, 2025

The Spanish National Health Survey tracks health care outcomes through representative samples of the Spanish population.
A Spanish research team used survey data to explore the relationship between ADHD symptoms and dental and gum health in a representative sample of 3,402 Spanish children aged 6 to 14.
While previous studies have found associations between ADHD and poor dental health, they have not fully accounted for such important determinants of poor oral health as socioeconomic status, dental hygiene, or diet.
The team therefore adjusted for sociodemographic factors, lifestyle variables, and oral hygiene behaviors. More specifically, they adjusted for sex, age, social class, parental education, exposure to tobacco smoke, consumption of sweets, consumption of sugary drinks, use of asthma or allergy medication, adequate oral hygiene behavior of children, adherence to regular dental visits, parental adequate oral hygiene behavior, and parental adherence to regular dental visits.
With those adjustments, children with ADHD symptoms had over twice the incidence of dental caries (cavities) as their counterparts without ADHD symptoms.
Tooth extractions and dental restorations also occurred with over 40% greater frequency in children with ADHD symptoms.
Gum bleeding, a sign of gum disease, was more than 60% more common among children with ADHD symptoms than among their non-ADHD peers.
Importantly, excluding children with daily sugar consumption, which left 1,693 children in the sample, made no difference in the outcome for cavities.
Excluding children with poor oral hygiene habits, which left 1,657 children in the sample, those with ADHD had 2.5-fold more caries than their non-ADHD counterparts.
Excluding children of low social class, which left 1,827 children in the sample, those with ADHD had 2.6-fold more caries than their non-ADHD counterparts.
Turning to a different method to address potential confounding factors, the team used nearest-neighbor propensity score matching to create virtual controls. This compared 461 children with ADHD to 461 carefully matched children without ADHD.
This time, children with ADHD symptoms had just under twice the incidence of cavities as their counterparts without ADHD symptoms, but 60% more tooth extractions and about 75% more dental restorations. The difference in gum bleeding became nonsignificant.
Noting that “The increased risk of caries was maintained when the analyses were restricted to middle/high social class families and children with low sugar intake, good oral hygiene behaviors and regular dental visits,” the team concluded, “Children with ADHD symptoms in Spain had worse oral health indicators than those without ADHD symptoms. Our results suggest that the association of ADHD symptoms with caries was independent of socioeconomic level, cariogenic diet, frequency of toothbrushing, and dental visits.”
Lucía Fernández-Arce, José Manuel Martínez-Pérez, Miguel García-Villarino, María Del Mar Fernández-Álvarez, Rubén Martín-Payo, and Alberto Lana, “Symptoms of Attention Deficit Hyperactivity Disorder and Oral Health Problems among Children in Spain,” Caries Research (2025), 59(1):35-45, https://doi.org/10.1159/000541013.
In recent years, there has been growing interest in understanding the connection between our gut microbiota (the community of microorganisms in our digestive system) and various neurodevelopmental disorders like autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). A new study by Shunya Kurokawa and colleagues dives deeper into this area, comparing dietary diversity and gut microbial diversity among children with ASD, ADHD, their normally-developing siblings, and unrelated volunteer controls. Let's unpack what they found and what it means.
The Study Setup
The researchers recruited children aged 6-12 years diagnosed with ASD and/or ADHD, along with their non-ASD/ADHD siblings and the unrelated non-ASD/ADHD volunteers. The diagnoses were confirmed using standardized assessments like the Autism Diagnostic Observation Schedule-2 (ADOS-2). The study looked at gut microbial diversity using advanced DNA extraction and sequencing techniques, comparing alpha-diversity indices (which reflect the variety and evenness of microbial species within each gut sample) across different groups. They also assessed dietary diversity through standardized questionnaires.
Key Findings
The study included 98 subjects, comprising children with ASD, ADHD, both ASD and ADHD, their non-ASD/ADHD siblings, and the unrelated controls. Here's what they discovered:
Gut Microbial Diversity: The researchers found significant differences in alpha-diversity indices (like Chao 1 and Shannon index) among the groups. Notably, children with ASD had lower gut microbial diversity compared to unrelated neurotypical controls. This suggests disorder-specific differences in gut microbiota, particularly in children with ASD.
Dietary Diversity: Surprisingly, dietary diversity (assessed using the Shannon index) did not differ significantly among the groups. This finding implies that while gut microbial diversity showed disorder-specific patterns, diet diversity itself might not be the primary factor driving these differences.
What Does This Mean?
The study highlights intriguing connections between gut microbiota and neurodevelopmental disorders like ASD and ADHD. The lower gut microbial diversity observed in children with ASD points towards potential links between gut health and the pathophysiology of ASD. Understanding these connections is crucial for developing targeted therapeutic interventions.
Implications and Future Directions
This research underscores the importance of considering gut microbiota in the context of neurodevelopmental disorders. Moving forward, future studies should account for factors like co-occurrence of ASD and ADHD, as well as carefully control for dietary influences. This will help unravel the complex interplay between gut microbiota, diet, and neurodevelopmental disorders, paving the way for innovative treatments and interventions.
In summary, studies like this shed light on the intricate relationship between our gut health, diet, and brain function. By unraveling these connections, researchers are opening new avenues for understanding and potentially treating conditions like ASD and ADHD.
In December 2016, the U.S. Food and Drug Administration (FDA) warned “that repeated or lengthy use of general anesthetic and sedation drugs during surgeries or procedures in children younger than 3 years or in pregnant women during their third trimester may affect the development of children’s brains.” The FDA adds, “Health care professionals should balance the benefits of appropriate anesthesia against the potential risks, especially for procedures lasting longer than 3 hours or if multiple procedures are required in children under 3 years,” and “Studies in pregnant and young animals have shown that using these drugs for more than 3 hours caused widespread loss of brain nerve cells.”
That raises a concern that such exposure could lead to increased risk of psychiatric disorders, including ADHD.
Noting “There are inconsistent reports regarding the association between general anesthesia and adverse neurodevelopmental and behavioral disorders in children,” a South Korean study team conducted a nationwide population study to explore possible associations through the country’s single-payer health insurance database that covers roughly 97% of all residents.
The team looked at the cohort of all children born in Korea between 2008 and 2009, and followed them until December 31, 2017. They identified 93,717 children in this cohort who during surgery received general anesthesia with endotracheal intubation (a tube inserted down the trachea), and matched them with an equal number of children who were not exposed to general anesthesia.
The team matched the unexposed group with the exposed group by age, sex, birth weight, residential area at birth, and economic status.
They then assessed both groups for subsequent diagnoses of ADHD.
In general, children exposed to general anesthesia were found to have a 40% greater risk of subsequently being diagnosed with ADHD than their unexposed peers.
This effect was found to be dose dependent by several measures:
All three measures were highly significant.
The authors concluded, “exposure to general anesthesia with ETI [endotracheal intubation] in children is associated with an increased risk of ADHD … We must recognize the possible neurodevelopmental risk resulting from general anesthesia exposure, inform patients and parents regarding this risk, and emphasize the importance of close monitoring of mental health. However, the risk from anesthesia exposure is not superior to the importance of medical procedures. Specific research is needed for the development of safer anesthetic drugs and doses.”
The U.S. government released a sweeping document titled The MAHA Report: Making Our Children Healthy Again, developed by the President’s “Make America Healthy Again” Commission. Chaired by public figures and physicians with ties to the current administration, the report presents a broad diagnosis of what it calls a national health crisis among children. It cites rising rates of obesity, diabetes, allergies, mental illness, neurodevelopmental disorders, and chronic disease as signs of a generation at risk.
The report's overarching goal is to shift U.S. health policy away from reactive, pharmaceutical-based care and toward prevention, resilience, and long-term well-being. It emphasizes reforming the food system, reducing environmental chemical exposure, addressing lifestyle factors like physical inactivity and screen overuse, and rethinking what it calls the “overmedicalization” of American children.
While some of the report’s arguments are steeped in political rhetoric and controversial claims—particularly around vaccines and mental health diagnoses—others are rooted in well-established public health science. This blog aims to highlight where the MAHA Report gets the science right, especially as it relates to childhood health and ADHD.
Although the MAHA Report contains several debatable assertions, it also outlines six key public health priorities that are well-supported by decades of research. If implemented thoughtfully, these recommendations might make a meaningful difference in the health of American children:
Reduce Ultra-Processed Food (UPF) Consumption
UPFs now make up nearly 70% of children’s daily calories. These foods are high in added sugars, refined starches, unhealthy fats, and chemical additives, but low in nutrients. Studies—including a 2019 NIH-controlled feeding study—show that UPFs promote weight gain, overeating, and metabolic dysfunction. What can help: Tax incentives for fresh food retailers, improved school meals, front-of-pack labeling, and food industry regulation.
Promote Physical Activity and Limiting Sedentary Time
Most American children don’t get the recommended 60 minutes of physical activity per day. This contributes to obesity, cardiovascular risk, and even mental health issues. Physical activity is known to improve attention, mood, sleep, and self-regulation. What can help: Mandatory daily PE, school recess policies, walkable community infrastructure, and screen-time education.
Addressing Sleep Deprivation
Teens today sleep less than they did a decade ago, in part due to screen use and early school start times. Sleep loss is linked to depression, suicide risk, poor academic performance, and metabolic problems. What can help: Later school start times, family education about sleep hygiene, and limits on evening screen exposure.
Improving Maternal and Early Childhood Nutrition
The report indirectly supports actions that are backed by strong evidence: encouraging breastfeeding, supporting maternal whole-food diets, and improving infant nutrition. These are known to reduce chronic disease risk later in life.
ADHD is one of the most discussed neurodevelopmental disorders in the MAHA Report, but many of its claims about ADHD are misleading, oversimplified, or inconsistent with decades of scientific evidence, much of which is described in the International Consensus Statement on ADHD, and other references given below.
This is true. Diagnosis rates have risen over the past two decades, due in part to better recognition, broadened diagnostic criteria, and changes in healthcare access. Diagnosis rates in some parts of the country are too high, but we don’t know why. That should be addressed and investigated. MAHA attributes increasing diagnoses to ‘overmedicalization’. That is a hypothesis worth testing but not a conclusion we can draw from available data.
These have been associated with ADHD but have not been documented as causes. ADHD is highly heritable, with genetic factors accounting for 70–80% of the risk. Unlike genetic studies, environmental risk studies are compromised by confounding variables. There are good reasons to address these issues but doing so is unlikely to reduce diagnostic rates of ADHD.
❌ Inaccurate: ADHD medications don’t work long-term.
The report criticizes stimulant use but fails to note that ADHD medications are among the most effective psychiatric treatments, especially when consistently used. They cite the MTA study’s long term outcome study of kids assigned to medication vs. placebo as showing medications don’t work in the long term. But that comparison is flawed because during the follow-up period, many kids on medication stopped taking them and many on placebo started taking medications. Many studies document that medications for ADHD protect against many real-world outcomes such as accidental injuries, substance abuse and even premature death.
Despite the issues discussed above, the MAHA Report can indirectly help children and adults with ADHD by pushing for systemic changes that reduce ultra-processed food consumption, increase physical activity, and motivate better sleep practices.
In other words, you don’t need to reject the diagnosis of ADHD to support broader changes in how we feed, educate, and care for children. A more supportive, less toxic environment benefits everyone—including those with ADHD.
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.
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