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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.”
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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.
For many ADHD patients, getting properly diagnosed and starting meds is only half the battle. The next step is figuring out the exact right dose. Historically, clinical guidelines have provided scant guidance on this critical step. This lack of direction can inadvertently foster two extremes in clinical practice: therapeutic inertia (settling for a subtherapeutic dose that leaves symptoms undertreated) or uncritical escalation (driving doses higher and higher beyond licensed limits without meaningful benefit).
To clear up this pharmacological gray area, an international team of researchers published the first comprehensive dose-effect network meta-analysis of ADHD medications in The Lancet Psychiatry. By pulling together a massive vault of clinical trial data, they mapped out exactly how efficacy and tolerability shift as doses increase.
Traditional meta-analyses evaluate head-to-head, pairwise data, comparing one drug at a specific dose directly against a placebo. However, this study utilized an advanced Bayesian hierarchical network model using restricted cubic splines.
This mathematical framework allowed the researchers to combine both direct trial data and indirect evidence simultaneously across 113 double-blind randomized controlled trials (RCTs). In total, the study evaluated data from 14,138 children/adolescents and 11,016 adults. By standardizing various formulations into basic equivalents (e.g., converting amphetamines to dextroamphetamine equivalents), they created a clear, unified map of dose ranges.
The study yielded distinct dose-response curves depending on the patient's age and the specific medication class. Rather than a linear trend in which "more medicine equals more benefit," most treatments reach a clear statistical plateau or ceiling.
For Children and Adolescents (under 18)
In the pediatric population, medications hit clear peak efficacy boundaries:
For both amphetamines and guanfacine, escalating the dosage past these points resulted in U-shaped curves, meaning further dose hikes yielded diminishing group-level symptom reduction.
For Adults (18 and older)
Adult profiles showed slightly different trajectories:
The ultimate goal of this landmark analysis is to guide shared decision-making between clinicians, patients, and families. The results send a dual message to the medical community:
A medication's true efficacy hinges on its tolerability, typically measured by how often patients discontinue treatment due to severe side effects. For amphetamines, this dropout risk scales linearly with dosage, notably exceeding placebo in children above 25 mg/day and becoming prominent in adults past 50 mg/day. In contrast, methylphenidate shows no clear dose-dependent dropout risk in pediatric patients, whereas adults face a steep risk curve: increasing the dose from 60 mg/day to 90 mg/day raises the dropout risk from 7.3% to 10.0% for only modest symptom relief. Finally, youth taking guanfacine experience a sharp climb in discontinuation risks, reaching a 9.8% median risk at 4 mg/day before data limitations obscure further trends.
The authors strongly emphasize that these findings represent group averages. Because individual metabolism, genetics, and comorbidities vary widely, some specific patients may legitimately require and tolerate higher off-label doses. However, if an unusually high dose is needed, the study suggests it should prompt a careful clinical pause, either to reassess for co-occurring conditions (like anxiety, autism, or sleep disorders) or to manage realistic expectations regarding what the medication can achieve.
The persistent shortage of ADHD medications has been more than a simple annoyance for patients at the pharmacy; the inconsistent availability of these medications has had deep impacts on the daily lives of those struggling without them. While public discourse has pointed fingers at over-prescribing or at restrictive DEA quotas, a recent economic evaluation in JAMA Health Forum suggests we’ve been looking in the wrong direction for an answer to what is causing this.
The reality of the shortage is less about increased demand and more about a fragile, globalized supply chain that snapped at a critical link.
Debunking the "Quota Myth":
The prevailing narrative suggested that the Drug Enforcement Administration (DEA) was stifling production by refusing to raise quotas. However, the data tells a different story. In 2022, manufacturers collectively met only about 70% of their allotted production quotas.
So we know that the problem wasn't that this DEA quota ceiling was too low. In fact, most manufacturers couldn't even reach it. Even when accounting for exports and domestic retail, production remained significantly below the legal limit. Even if the DEA had doubled its quotas, these medications still likely wouldn't have magically appeared on pharmacy shelves.
The most striking finding in the study is the correlation between the shortage and a sharp decline in the import of raw Active Pharmaceutical Ingredients (APIs). For the past decade, Germany has accounted for over 85% of US amphetamine imports. In 2022, these imports dropped by approximately 36.7%. When the API doesn't arrive at the factory, production for medium and small manufacturers grinds to a halt. Unlike larger pharmaceutical giants, these smaller players often lack the inventory cushion or flexibility to quickly pivot to a new supplier.
When the primary supply of amphetamine-based stimulants (like Adderall) faltered, it triggered a secondary crisis. Patients and clinicians, seeking alternatives, shifted toward lisdexamfetamine (Vyvanse) and methylphenidate (Ritalin/Concerta).
If we view this shortage purely through a regulatory or clinical lens, we miss the underlying cause of the crisis. The pharmaceutical industry has become a victim of its reliance on "just-in-time manufacturing” and highly concentrated sourcing. Because over 30% of APIs for the US market are produced in just one or two facilities globally, the system isn't just inefficient; it’s brittle. We are, in a sense, trapped in a system that prioritizes cost-reduction over the resilience required for public health.
The researchers suggest several policy shifts to prevent a repeat of this supply chain failure:
The ADHD medication shortage wasn't a failure of clinical oversight or a sudden surge in "TikTok-driven diagnoses”, as many have suggested. It was a failure of logistics. It reminds us that the path from a lab in Germany to a patient's hand in the US is far more precarious than we realized.
ADHD is a neurodevelopmental condition rooted in delayed or atypical maturation of the prefrontal cortex (the brain region that governs self-regulation). This maturational lag underlies the hallmark difficulties with attention, hyperactivity, and impulsivity, and also impairs what researchers call executive function: the cognitive toolkit we rely on for working memory, impulse control, mental flexibility, emotional regulation, and the ability to tolerate delays in reward.
The Background:
Standard treatments work through two main routes. Stimulant and non-stimulant medications are considered very safe and effective treatments, but are not without risk of side effects and are not appropriate for every ADHD patient. Behavioral and psychosocial interventions can improve self-regulation and social functioning, but they require sustained effort and produce variable results. These limitations have kept the search for better alternatives active.
One candidate that has drawn growing attention is transcranial direct current stimulation (tDCS). The technique is appealingly simple: a weak electrical current is applied to the scalp through small electrodes, modulating the excitability of neurons in the underlying cortex without requiring surgery, anesthesia, or significant discomfort. Its safety profile and ease of use have made it attractive to researchers.
The Study:
A newly published meta-analysis set out to give the technique its most rigorous test yet, pooling results from randomized controlled trials, including crossover designs, that compared active tDCS against sham stimulation in people with ADHD across all age groups.
The Results:
The findings were consistently null. Across seven trials enrolling 303 participants, tDCS produced no significant reduction in overall ADHD symptom severity compared with sham. Breaking symptoms into their components made no difference: neither hyperactivity/impulsivity nor inattention improved. Turning to executive function, 18 studies with 872 participants found no meaningful gain in inhibitory control, and 12 studies with 506 participants found the same for working memory. Smaller bodies of evidence, including three studies on cognitive flexibility (122 participants) and two on hot executive function, the motivational and emotional dimension of self-regulation (86 participants), similarly came up empty. Variation in outcomes across studies was small to moderate, and there was no evidence of publication bias skewing the picture.
The authors’ conclusion was succinct: tDCS was well tolerated but “did not demonstrate significant overall efficacy for core ADHD symptoms or executive functions.”
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