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June 13, 2025

Study Finds Association Between Childhood ADHD and Poor Dental Health

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.”

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Study Finds Association Between Childhood ADHD and Poor Dental Health

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.”

June 13, 2025
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A Lesson in Correlation Versus Causation : Maternal Smoking and ADHD Risk in Children

Meta-analysis Finds Strong Link Between Maternal Smoking During Pregnancy and Increased Risk of ADHD in Children

This new meta-analysis confirms what other meta-analysis have already shown, i.e, that there exists in the population an association between maternal smoking during pregnancy and ADHD in their offspring.  But reader beware, association does not mean causation.

The team identified 55 studies with quantitative data suitable for meta-analysis, including 11 case-control, 13 cross-sectional, and 31 retrospective/prospective cohort studies. 

Altogether they combined more than four million persons in countries spanning six continents, including the United States, Finland, Sweden, Brazil, the Netherlands, Japan, the UK, Spain, China, Australia, New Zealand, Norway, Canada, France, Sweden, South Korea, Turkey, Romania, Bulgaria, Lithuania, Germany, Denmark, Egypt, and India.

Meta-analysis of all 55 studies found that offspring of mothers who smoked tobacco during pregnancy were about 70% more likely to develop ADHD than offspring of mothers who did not smoke during pregnancy.

Because variation in outcomes across studies was very high, the team performed subgroup analyses to explore potential sources of this heterogeneity. 

Comparing study designs, cohort studies reported roughly 50% greater odds of ADHD among children of mothers who smoked during pregnancy, whereas case-control studies reported roughly 70% greater odds and cross-sectional studies 2.3-fold greater odds.

Studies using the most reliable method of determining ADHD – clinical interview/professional diagnosis – reported 90% greater odds, contrasting with 66% through medical records/databases and 58% through self-report by child/parent or through teacher report.

Good quality studies reported roughly 75% greater odds. 

Studies with sample sizes above two thousand similarly found 70% greater odds.

There was no sign of publication bias using the more commonly used Egger’s test, but a marginal indication of publication bias using Begg’s test. Performing a standard correction reduced the effect size, indicating that the offspring of mothers who smoked tobacco during pregnancy were over 50% more likely to develop ADHD than the offspring of mothers who did not smoke during pregnancy.

The team concluded, “This systematic review and meta-analysis of 55 studies, encompassing over four million participants, provides compelling evidence that maternal tobacco smoking during pregnancy significantly increases the odds of ADHD in children … These findings underscore the critical need for public health interventions aimed at reducing tobacco smoking during pregnancy.”

However, we disagree with this conclusion; The authors ignore substantial evidence showing that maternal smoking during pregnancy is confounded by maternal ADHD. These mothers transmit ADHD via genetics, not via their smoking. This study should be seen not as "...[further evidence that smoking during pregnancy causes ADHD.] ", but as a lesson in how easy it can be to see correlation as causation.

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June 10, 2025
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Meta-analysis Finds Little Evidence of Efficacy for Animal-Assisted Interventions for Treating Childhood ADHD

Study Background:

Animal-assisted interventions (AAIs) involve structured interactions with animals, designed and carried out by mental health teams assisted by trained human–animal professionals, to achieve specific therapeutic or educational goals. While a wide variety of animals may be used, horses and dogs tend to predominate. These interventions often involve physical contact, imitation, and play aimed at reducing stress and generating affection. Previous research has suggested that AAI to those with a range of developmental and mental health conditions.

Just how effective are they for treating ADHD in children and adolescents? Recent years have seen an increase in studies into AAIs for children with ADHD, but previous systematic reviews have not included quantitative meta-analysis to evaluate efficacy.

The Study:

A Chinese study team based in Nanjing set out to remedy that with a systematic search of the peer-reviewed published medical literature aimed at performing meta-analyses of efficacy.

The team limited its search to randomized controlled trials (RCTs) and pre–post single-group studies involving children and adolescents diagnosed with ADHD.

Meta-analysis of five studies with a combined total of 95 participants reported no significant effect of AAIs on ADHD symptom severity. There was negligible variation (heterogeneity) in outcomes among the studies.

Similarly, meta-analysis of the six studies encompassing 323 individuals found no significant improvements in social behavior. There was no heterogeneity and no sign of publication bias. Breaking that down into subcategories of social interaction (4 studies, 190 persons), social skill (3 studies, 53 persons), and problem behavior (4 studies, 80 participants) made no difference.

Likewise, meta-analysis of the three studies encompassing 61 individuals found no significant improvements in emotional control. Again, there was no heterogeneity and no sign of publication bias.

Three studies combining 56 participants reported no significant reductions in anxiety and depression, again with no heterogeneity and no sign of publication bias.

However, meta-analyses of five studies encompassing 194 individuals found a medium effect size association between AAIs and declines in attention problems, and a medium-to-large effect size improvement in learning and cognition. Heterogeneity was negligible to low.

Finally, meta-analysis of three studies combining 95 participants reported a large effect size improvement in motor proficiency, with moderate heterogeneity.

The Conclusion:

The team concluded, “As an ADHD management strategy complementary to gold-standard approaches, such as medication or multimodal interventions, AAIs did not appear to be more effective in improving the majority of core ADHD outcomes in children. Future studies should incorporate rigorous study designs with large sample sizes and a standard protocol to achieve more valid and reliable conclusions.”

June 5, 2025
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How ADHD and ODD Symptoms in Teens Can Affect Long-Term Education Outcomes

A recent Finnish study offers important insights into how symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD) in adolescence can shape academic performance, and even influence educational outcomes well into adulthood.  Children and teens with ODD often show a pattern of angry, irritable moods, arguing with adults, and defying rules or requests. They may lose their temper easily, be quick to blame others for mistakes, and deliberately annoy people. 

The researchers followed participants from the Northern Finland Birth Cohort of 1986, a large, population-based study. They looked at over 6,000 teens whose parents reported symptoms of ADHD and ODD when the children were 15–16 years old. The team then tracked their academic performance at age 16 and their highest level of education by age 32.

ADHD, ODD, and Academic Performance

ADHD is well-known for affecting school performance, often linked to difficulties with attention, impulse control, and executive functioning. ODD, characterized by patterns of irritability, defiance, and hostility toward authority figures, is less studied in this context, especially when it appears without ADHD.

The study found that both disorders, whether occurring separately or in combination, were associated with poorer grades at age 16. However, teens with ADHD symptoms performed worse than those with only ODD symptoms. Interestingly, students with both ADHD and ODD symptoms had the most pronounced academic struggles, but their performance didn’t significantly differ from the ADHD-only group at that age.

Long-Term Educational Impact

By age 32, the effects were even more striking. Participants with both ADHD and ODD symptoms were the least likely to attend or graduate from higher education institutions. Only about 10% of them reached that level, compared to over 40% of those without these symptoms.

Even after accounting for other influences, such as parental education, family structure, and additional psychiatric conditions, the findings held. This suggests that the combination of ADHD and ODD symptoms in adolescence may uniquely disrupt the educational path.

For adolescent girls with ODD symptoms, the impact was particularly notable: they were significantly more likely to complete only the mandatory nine years of schooling.

Why This Matters

These results underscore the lasting effects that behavioral and emotional challenges in adolescence can have. While schools often focus on immediate academic outcomes, this study highlights the importance of early identification and support, not just for ADHD but for ODD as well.

Parents and educators play a crucial role in shaping future outcomes for children and adolescents with ADHD. Recognizing early signs of attention problems, emotional dysregulation, or defiance—and responding with appropriate interventions—could help redirect educational trajectories and open up opportunities down the line.

In short, it’s not just about managing classroom behavior. It’s about supporting long-term potential. When ADHD and ODD symptoms show up in adolescence, they don’t just make school harder—they can limit a student’s entire educational future. Early support and understanding can make a lasting difference.

May 29, 2025
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What the MAHA Report Gets Right—and Wrong—About ADHD and Children's Health

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.

Some of the Good Ideas in the MAHA Report:

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.

What MAHA Says About ADHD:

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 ADHDand other references given below.

✔️ Accurate: ADHD diagnoses are increasing.

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.

❌ Misleading: ADHD is caused by processed food, screen time, or chemical exposures.

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.

How the MAHA Report Could Still Help People with ADHD:

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.

May 28, 2025
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UK Nationwide Population Study Finds ADHD Associated with Reduced Life Expectancy

The United Kingdom has a National Health Service (NHS) that encompasses virtually its entire population, with free access. The NHS records facilitate conducting nationwide studies.

The Study

Using electronic health records from 794 primary care practices (roughly one in ten UK practices), largely representative of the UK population, a research team used mortality data to explore the life expectancy of adults diagnosed with ADHD compared with adults not diagnosed with ADHD.

For each adult diagnosed with ADHD, the team sampled ten controls matched by age, sex, and primary care practice. They identified 30,039 individuals with an ADHD diagnosis in their electronic health records and matched them with 300,390 without an ADHD diagnosis.

The team also gathered data on socioeconomic deprivation, diabetes, elevated cholesterol, hardening of the coronary arteries, high blood pressure, chronic respiratory disease, epilepsy, anxiety, depression, severe mental illness, self-harm/suicide, autism, intellectual disability, personality disorder, current smoking, and potentially harmful alcohol use. All these conditions examined at baseline were more common among participants with ADHD than comparison participants.

Both men and women with ADHD were about twice as likely to die during follow-up as Those without ADHD. A diagnosis of ADHD was associated with a 6.8-year reduction of life expectancy in males and an 8.6-year reduction of life expectancy in females.

Conclusion

The authors wrote, “We believe that this is unlikely to be because of ADHD itself and likely caused by modifiable factors such as smoking, unmet mental and physical health support, and unmet treatment needs. The findings illustrate an important inequity that demands urgent attention.”

They also noted, “…we did not adjust for socioeconomic status (SES), as we believe that SES is best understood as part of the causal pathway between ADHD and premature mortality (i.e. SES is a mediator).” These results confirm other studies which also document that those with ADHD have a decreased life expectancy, primarily due to accidents and suicide. 

May 23, 2025
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Transcranial Direct Current Stimulation for ADHD Symptoms and Executive Function

Meta-analysis finds benefits of transcranial direct current stimulation for ADHD symptoms and executive function—but evidence remains weak

Background

A meta-analysis examined whether noninvasive brain stimulation (NIBS) techniques could help reduce core symptoms of ADHD and improve cognitive function. NIBS refers to techniques that stimulate brain activity using low electrical or magnetic currents applied from outside the head. They studied transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), while newer methods like tRNS (random noise) and tACS (alternating current) lacked enough studies to be included in the analysis.

Methods

Only randomized controlled trials (RCTs)—considered the gold standard in clinical research—were included in the review. For tDCS, the results were promising:

-A meta-analysis of 12 studies (582 participants) showed small but statistically significant improvements in inhibitory control (the ability to stop or delay responses).

-Nine studies (390 participants) showed small-to-medium improvements in working memory.

-Two smaller studies (94 participants) hinted at improvement in cognitive flexibility, but the results were not strong enough to be considered reliable.

-Seven studies (277 participants) found medium-to-large improvements in linattention, though results varied significantly between studies.

 Hyperactivity and impulsivity showed some improvement, but again, the number of studies was too small to draw firm conclusions.

 For rTMS, however, the results were not as encouraging. A meta-analysis of three studies (137 participants) found no significant improvement in ADHD symptoms.

Conclusion

While the results suggest that tDCS may offer some benefit for executive functions and attention in people with ADHD—especially when targeting specific brain areas like the F3/F4 regions (roughly over the dorsolateral prefrontal cortex)—the authors emphasize the need for further research. Most studies didn’t include long-term follow-up, and there’s still a lack of consistency in how stimulation is applied across studies.  Moreover, even when positive findings emerged for executive functions is not clear how these translate into changes that are meaningful for the patient.

Importantly, this study doesn’t suggest that NIBS should replace standard treatments. Although the paper highlights challenges with medication adherence and side effects, ADHD medications and behavior therapies remain the most well-established and effective treatments for most patients. The improvements seen with NIBS so far are relatively small and preliminary in comparison.

Instead, the findings support the idea that NIBS could one day serve as a complementary tool—especially for individuals who don’t respond well to existing treatments. But until more rigorous and long-term studies are done, NIBS should be viewed as an experimental approach, not a substitute.

 

 

 

May 22, 2025
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Seven New Meta-analyses Suggest Wide Range of Benefits from Exercise for Persons with ADHD

Seven New Meta-analyses Suggest Wide Range of Benefits from Exercise for Persons with ADHD

ADHD is associated with deficits in executive functions. These are mental processes that enable individuals to plan, focus attention, manage tasks, and regulate emotions. These skills encompass working memory, cognitive flexibility, and inhibitory control, which are crucial for goal-directed behavior and decision-making. 

Working memory, which temporarily stores and processes information, contributes to language development by helping individuals make sense of what they read or hear.  

Cognitive flexibility refers to the ability to change perspectives, adapt thinking strategies, adjust to changing needs and priorities, recognize errors, and grasp opportunities.  

Inhibition switching involves intentional control of attention and emotions, suppressing automatic responses when necessary to prevent inappropriate behavior.  

These elements are critical to academic, social, and professional success. 

An international study team (Li et al.) conducted a meta-analysis of randomized controlled trials (RCTs) to explore the efficacy of physical activity for improving executive functions among children with ADHD aged 6 to 12. 

Meta-analysis of eleven RCTs encompassing 388 children reported a medium-to-large effect size improvement in cognitive flexibility. However, it found no benefit from aerobic exercise (such as running, jumping). When limited to the nine studies with 301 children that focused on cognitively engaging exercise (such as soccer and water sports that require constant monitoring of other players and strategizing), it found a large effect size improvement. Correcting for possible publication bias had no effect on the outcome. 

Meta-analysis of nine RCTs totaling 398 children reported a large effect size improvement in working memory. Once again, it found no benefit from aerobic exercise. Focusing on the seven RCTs with 288 children that used cognitively engaging exercise, it found a very large effect size improvement. There was no sign of publication bias. 

Meta-analysis of fourteen RCTs combining 579 children reported a small-to-medium effect size improvement in inhibition switching. But whereas it found a medium effect size improvement for shorter interventions of less than an hour (eight RCTs, 334 children), it found no benefit from interventions lasting an hour or more (six RCTs, 245 children. Again, there was no sign of publication bias. 

The team concluded, “Our study shows that physical activity interventions have a positive effect on improving executive function in school-age children with ADHD, with cognitive-engaging exercises showing greater benefits across three executive function measures.” 

A Chinese study team (Yang et al.) performed a related meta-analysis on the effect of exercise on inhibitory control in adults. Combining eight RCTs with a total of 372 participants, it reported a very large effect size improvement in inhibitory control, primarily from regular exercise. However, the effects were heavily influenced by a couple of outliers. The team claimed to have performed a sensitivity analysis but offered no evidence. Likewise, they noted signs of publication bias but did not use the standard trim-and-fill analysis to correct for it. 

Another Chinese study team (Xiangqin Song et al.) examined the effect of exercise on working memory in children and adolescents.  

Meta-analysis of 17 RCTs encompassing 419 participants found a medium effect size improvement in working memory. The large effect size improvement for cognitive aerobic exercise (4 RCTs, 233 participants) was twice the effect size for simple aerobic exercise (8 RCTs, 397 participants), though this meta-analysis still found a small-to-medium effect size gain from the latter. There was no sign of publication bias.  

The team concluded, “The results indicate that cognitive-aerobic exercise and ball sports are significantly more effective than other types of exercise interventions in improving working memory. This difference may be attributed to the varying cognitive load, task complexity, and the degree of activation of executive functions across different exercise types. The findings suggest that when designing exercise interventions for children with ADHD, priority should be given to exercise types with higher cognitive load in order to more effectively enhance working memory.” 

A joint Australian-U.S. team (Singh et al.) conducted a meta-meta-analysis on the effect of exercise on executive functions, that is, a meta-analysis of previous meta-analyses of RCTs.  

Combining ten separate meta-analyses with well over 2,800 children and adolescents with ADHD, it reported large effect size improvements in executive functions overall. There was no further breakdown by type of executive function and type of physical activity.  

The team concluded, “While exercise was seen to have a moderate and similar positive impact across all populations with respect to general cognition and memory, benefits for executive function were particularly marked in individuals with ADHD. This subgroup was unique in demonstrating a large effect size. This could be attributed to the task selection and the fact that many ADHD studies involved children. While the exact reason for this finding is unclear, there is evidence to suggest that impairments in executive function are common among individuals with ADHD. As such, it is plausible that this population may have a greater capacity for improvement due to starting from a lower baseline, compared with those with ‘normal’ executive function.” 

Another Chinese study team (Yagang Song et al.) performed a meta-analysis of RCTs examining the effects of physical exercise on anxiety, depression, and emotion regulation among children and adolescents with ADHD.  

Meta-analysis of eleven studies with a combined total of 384 participants reported a medium effect size reduction in symptoms of anxiety, with a dose-effect response. Physical exercise once a week had no significant effect, while twice a week was associated with a medium effect size reduction, and three or more times a week with a very large effect size improvement. Moderate intensity exercise was three times more effective than low intensity exercise.  

Meta-analysis of seven studies encompassing 187 individuals similarly reported a medium effect size reduction in symptoms of depression. Once again, moderate intensity was far more effective than low intensity exercise. 

Meta-analysis of seven studies totaling 429 children and adolescents reported a very large effect size improvement in emotion regulation, especially for physical exercise conducted at least twice a week

There was no sign of publication bias in the anxiety, depression, or emotion regulation findings. 

The team concluded, “Physical exercise demonstrated a substantial overall impact on enhancing anxiety, depression, and emotional regulation in children with ADHD, exhibiting a dose-response effect correlated with the period, frequency, duration, and intensity of the exercise. This investigation ... presents an additional evidence-based therapeutic approach for the considerable number of children with ADHD who are not appropriate candidates for pharmacological intervention.” 

A joint U.S.-Hong Kong study team (Liu et al.) performed a meta-analysis exploring the effect of physical exercise on motor proficiency. Motor proficiency includes both gross motor skills (like walking and running) and fine motor skills (like writing and buttoning).  

Meta-analysis of ten studies encompassing 413 children and adolescents with ADHD reported a very large effect size improvement in motor proficiency from physical exercise. The gains for object control, fine manual control, and manual coordination were roughly twice the gains for body coordination. There was no sign of publication bias. 

Finally, a Spanish research team (González-Devesa et al.) conducted a meta-analysis examining the effect of exercise on objectively measured sleep status among persons with ADHD. 

Meta-analysis of three RCTs with a combined total of 131 individuals that used accelerometers to measure sleep duration reported no significant effect one way or the other from exercise

The team concluded, “The existing evidence regarding the use of exercise to manage sleep problems in individuals with ADHD remains inconclusive. Preliminary findings from this review suggest a potential positive effect of exercise on self-reported sleep quality; however, its efficacy in improving sleep duration could not be confirmed.” 

The Take-Away:

An ideal exercise regimen for children with ADHD should focus on cognitively engaging physical activities rather than simple aerobic exercise. Sports and activities that require strategic thinking, attention to others’ actions, and rapid decision-making—such as soccer, martial arts, or water-based team sports—gave the best results, especially for working memory and cognitive flexibility. These types of exercise also show strong benefits for emotional regulation, reducing anxiety and depression, and enhancing motor proficiency.

To maximize benefits, the regimen should include moderate-intensity sessions at least two to three times per week, each lasting less than an hour, as longer durations appear less effective for improving inhibitory control. This structured, cognitively demanding approach offers an evidence-based, non-pharmacologic treatment option for children with ADHD, particularly for those who cannot or prefer not to use medication.  We need, however, more work to determine if exercise will provide the same symptom reduction and protection from adverse outcomes as has been shown for medications.

May 16, 2025
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How Early Parent–Child Interactions May Shape the Expression of ADHD Traits: A Longitudinal Study

We know that Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition with strong biological and genetic underpinnings; However, emerging research suggests that early environmental influences—particularly parent–child interactions—may shape how ADHD traits, such as impulsivity and delay aversion, are expressed during development.

This longitudinal study explored whether negative parental reactions during moments of delay contribute to the intensification of ADHD-related behaviors in preschool-aged children. A total of 112 mother–child pairs from the UK and Hong Kong participated. Children were screened for ADHD traits using the Strengths and Difficulties Questionnaire, ensuring a range of symptom severity. 

The experimental task—the Parent–Child Delay Frustration Task (PC-DeFT)—was designed to assess how children responded to brief, unpredictable waiting periods during a game-like activity, and how parents reacted in turn. During the task, children operated a button to change a red light to green, allowing their parent to retrieve a toy item. While most trials had no delay, six included unexpected 5–10 second pauses, creating mild frustration. Trained observers recorded children’s behavioral responses and parents' emotional reactions.

At follow-up (12–18 months later), teacher ratings revealed that children whose parents showed more negative reactions during delay trials (e.g., impatience, criticism) were more likely to exhibit increases in ADHD traits—especially impulsivity and difficulty waiting. Importantly, this link was mediated by increases in delay aversion, a motivational style where the child seeks to avoid frustrating waiting experiences. No such associations were found in free play or non-delay tasks, underscoring the specificity of this interaction.

The study’s findings suggest that, while these interactions do not cause ADHD, early social environments can influence how and when symptoms manifest. Interventions aimed at supporting positive parent–child interactions—particularly in challenging contexts like waiting—may help shape the developmental trajectory of children predisposed to ADHD.

May 15, 2025
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Study Finds LSD Microdosing No More Effective Than Placebo For ADHD

Double-blind Randomized Clinical Trial Finds LSD Microdosing No More Effective Than Placebo in Treating ADHD Symptoms

Double-blind Randomized Clinical Trial Finds LSD Microdosing No More Effective Than Placebo in Treating ADHD Symptoms

Background:

Stimulants, such as methylphenidate and amphetamines, are currently considered effective medications for treating ADHD. However, approximately one-third of patients do not have an adequate response to these treatments. Additionally, long-term adherence is relatively low, with only about half of the patients still using methylphenidate after six years. 

Recently, there has been increasing attention to the concept of microdosing with psychedelic drugs such as psilocybin and LSD. A microdose typically ranges from one-tenth to one-twentieth of a recreational dose and does not produce noticeable perceptual effects or interfere with daily activities.  

The Study:

A European research team recently published the findings of the first double-blind, placebo-controlled randomized clinical trial examining the safety and efficacy of repeated low doses of LSD in adults diagnosed with ADHD. 

The six-week trial took place at University Hospital in Basel, Switzerland, and Maastricht University, Netherlands. Participants, aged 18 to 65, had clinical diagnoses of ADHD with moderate to severe symptoms.  

The team excluded persons with a past or present diagnosis of psychotic disorders, substance use disorders, or other psychiatric or somatic disorders likely to require hospitalization or treatments. 

Participants were randomly assigned in a 1:1 ratio to receive either LSD or placebo. Neither study staff nor participants were aware of the assignments until the conclusion of the trial. 

During the six-week trial, participants received twice-weekly doses on-site, amounting to a total of 12 doses. Following the first and final doses, participants were asked to determine whether they had been administered LSD or a placebo in order to assess blinding. Four weeks after the conclusion of the microdosing period, participants returned for an evaluation of the treatment's safety and efficacy. 

Twenty-seven of the 53 participants were randomized to receive the LSD microdosing treatment in a liquid solution, and 26 to receive placebo. Placebo consisted of the same drinking solution, minus the microdose of LSD. 

The average age was 37, and 42% of participants were female. Forty-six of the 53 participants completed the study. 

Out of 29 participants, 21 from the LSD group and eight from the placebo group correctly guessed their allocation, totaling 63% overall.  

As assessed through the Adult ADHD Investigator Symptom Rating Scale, ADHD symptoms improved by 7.1 points in the LSD group and 8.9 points in the placebo group, with no significant difference between them. 

Regarding safety, the LSD group experienced nearly double the adverse events compared to the placebo group. None of the events in either group were classified as serious. The five most frequent adverse events were headache, nausea, fatigue, insomnia, and visual alterations, occurring around three times more frequently in the LSD group than in the placebo group. 

The team concluded, “although repeated low-dose LSD administration was safe in an outpatient setting, it failed to demonstrate efficacy compared with placebo in improving ADHD symptoms among adults.” 

Conclusion: Microdosing with LSD did not offer significant advantages over placebo in treating ADHD symptoms, despite being physically safe and well tolerated in the trial setting. This suggests that further research is needed to explore alternative treatments for ADHD.

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April 23, 2025
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