April 9, 2024

Exploring Gut Microbiota and Diet in Autism and ADHD: What Does the Research Say?


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.

Kurokawa S, Nomura K, Sanada K, Miyaho K, Ishii C, Fukuda S, Iwamoto C, Naraoka M, Yoneda S, Imafuku M, Matsuzaki J, Saito Y, Mimura M, Kishimoto T. A comparative study on dietary diversity and gut microbial diversity in children with autism spectrum disorder, attention-deficit hyperactivity disorder, their neurotypical siblings, and non-related neurotypical volunteers: a cross-sectional study. J Child Psychol Psychiatry. 2024 Apr 2. doi: 10.1111/jcpp.13962. Epub ahead of print. PMID: 38562118.

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NEWS TUESDAY: A Retrospective Study on Post–COVID-19 Mental Health Distress in 13 Million Youth

NEWS TUESDAY: A Retrospective Study on Post–COVID-19 Mental Health Distress in 13 Million Youth

Our research team conducted a study, published in the Journal of the American Academy of Child & Adolescent Psychiatry, to understand how COVID-19 (SARS-CoV-2) affects the mental health of young people. We used a method called Kaplan-Meier survival analysis to figure out how likely kids were to develop new mental health problems, including suicidal thoughts, within two years after being infected. We looked at medical records of 7.5 million children and 5.3 million teenagers who were part of the TriNetX Research Network. Importantly, we focused only on those who didn’t have any mental health issues before.

Of these young people, almost 300,000 children and over 220,000 teens had tested positive for COVID-19. The results were significant: children who had COVID-19 had a 15% chance of being diagnosed with a new mental health condition, compared to just 2.6% for children who didn’t get COVID-19. For teens, the chance was 19% for those infected and 5% for those not infected.

We found that the risk of developing new mental health issues was six times higher in children and four times higher in teens who had COVID-19. This shows that younger kids are more strongly affected.

The study also highlighted that COVID-19 was linked to higher rates of various mental health problems, especially in children. This means it’s really important to screen for mental health issues in young people after they’ve had COVID-19, particularly for those who had severe cases.

Overall, our findings point to the need for special support for kids and teens who may be more vulnerable after the pandemic. It’s clear that the mental health effects of COVID-19 go beyond just physical health, and it’s crucial that doctors and policymakers include mental health care in plans to help young people recover.

September 24, 2024

NEW STUDY: The Cumulative Impact of ADHD, ASD, and Intellectual Disabilities

Neurodevelopmental conditions often coexist, creating a complex web of challenges for affected individuals. A recent study by Hollingdale et al. delves into the cumulative effects of attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and intellectual disability (ID) on young people’s behavioral and socio-emotional well-being, as well as their overall functioning as rated by clinicians.

The researchers conducted a cross-sectional analysis of 2768 young individuals aged 3-17 years, with a mean age of approximately 11.5 years. Diagnostic information along with caregiver-rated behavioral and socio-emotional data, and clinician-rated functioning scores, were collected from electronic patient records at the point of initial diagnosis.

The study aimed to understand whether the number of neurodevelopmental conditions—ranging from one to three—correlates with more pronounced behavioral and socio-emotional issues, and lower levels of clinician-rated functioning. The behavioral and socio-emotional aspects were assessed using the Strengths and Difficulties Questionnaire, while the Children's Global Assessment Scale was used to evaluate clinician-rated functioning.

The findings revealed that young people with multiple neurodevelopmental conditions tend to exhibit higher levels of inattention and hyperactivity, greater peer-related problems, reduced prosocial behaviors, and poorer overall functioning. Interestingly, this cumulative impact was more evident in males compared to females, with females only showing significant cumulative effects in clinician-rated functioning.

This research underscores the importance of recognizing the compounded difficulties faced by young people with multiple neurodevelopmental conditions. It highlights the need for tailored interventions that address the unique and overlapping challenges presented by ADHD, ASD, and ID. For practitioners, understanding these cumulative effects is crucial for developing effective treatment plans that can better support the holistic development and well-being of these young individuals.

In conclusion, the presence of multiple neurodevelopmental conditions can significantly affect various domains of a young person’s life, with notable differences between males and females. This study provides a critical insight into the intricate nature of these conditions and calls for a more nuanced approach in both research and clinical practice.

June 18, 2024

How Effective Is Exercise in Treating ADHD?

New meta-analysis explores effectiveness of physical exercise as treatment for ADHD

Noting that "Growing evidence shows that moderate physical activity (PA) can improve psychological health through enhancement of neurotransmitter systems," and "PA may play a physiological role similar to stimulant medications by increasing dopamine and norepinephrine neurotransmitters, thereby alleviating the symptoms of ADHD," a Chinese team of researchers performed a comprehensive search of the peer-reviewed journal literature for studies exploring the effects of physical activity on ADHD symptoms.

They found nine before-after studies with a total of 232 participants, and fourteen two-group control studies with a total of 303 participants, that met the criteria for meta-analysis.

The meta-analysis of before-after studies found moderate reductions in inattention and moderate-to-strong reductions in hyperactivity/impulsivity. It also reported moderate reductions in emotional problems and small-to-moderate reductions in behavioral problems.

The effect was even stronger among unmediated participants. There was a very strong reduction in inattention and a strong reduction in hyperactivity/impulsivity.

The meta-analysis of two-group control studies found strong reductions in inattention, but no effect on hyperactivity/impulsivity. It also found no significant effect on emotional and behavioral problems.

There was no sign of publication bias in any of the meta-analyses.

The authors concluded, "Our results suggest that PA intervention could improve ADHD-related symptoms, especially inattention symptoms. However, due to a lot of confounders, such as age, gender, ADHD subtypes, the lack of rigorous double-blinded randomized-control studies, and the inconsistency of the PA program, our results still need to be interpreted with caution."

February 21, 2022

Global Data Indicates Gentle Quarter-century Decline in ADHD in Adolescents and Young Adults

A new study in the respected journal PLOS One analyzes data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) to examine trends in the incidence, prevalence, and disability-adjusted life-years associated with ADHD among adolescents and young adults aged 10 to 24 years between 1990 and 2021.  

The GBD 2021, released by the Institute for Health Metrics and Evaluation (U.S.), is a comprehensive global analysis of 371 diseases, injuries, and risk factors – such as ADHD – across 204 countries from 1990 to 2021. Its open-source data are publicly available. 

First, a distinction. Incidence measures the number of new cases of a disease that develop in a specific population each year. Prevalence measures the total number of existing cases – both new and pre-existing – in a population each year.   

The estimated global incidence of ADHD declined marginally from 12.61 per 100,000 population in 1990 to 11.89 per 100,000 population in 2021, representing an average annual decrease of 0.6% in age-standardized incidence. The rates observed were comparable between males and females. 

Regional trends varied: Western Europe had the highest rise in ADHD incidence (0.5% annually), while North Africa and the Middle East saw the largest drop (0.7% annually). Overall, a higher Socio-Demographic Index (SDI) is linked to a greater incidence, although it is far from a perfect fit. Nationally, showed the highest increase in ADHD incidence (1.15% annually), while Qatar showed the largest decrease with an annualized reduction of 1.77%. 

The estimated global prevalence of ADHD declined marginally from 2.38% in 1990 to 2.17% in 2021. Again, the decline was similar for males and females, and across all age groups (10-14, 15-19, 20-24). Higher SDI was associated with higher prevalence, but inconsistently. 

Disability-adjusted life-years (DALYs) combine years lost from early death and years lived with disability to measure disease burden. Globally, the age-standardized DALYs rate for ADHD decreased slightly from 30.3 per 100,000 population to 26.6 per 100,000 population, for an average annual decline of 0.6%. The decline occurred across age groups and was similar between males and females.  

The authors concluded that ADHD rates and related health burdens have generally declined over the past quarter century, though recent patterns are less consistent due to factors like socioeconomic changes and evolving diagnostic standards. Continued research is needed to improve the accuracy and accessibility of ADHD diagnosis and treatment to further reduce its global impact. 

 Take-Away:

The broader takeaway is one of cautious reassurance. Despite rising public awareness and diagnosis rates in many Western countries, the global picture over 25 years shows a gentle decline in ADHD burden among young people — not a crisis of escalating proportions. That said, the variation between regions suggests that access to diagnosis, cultural factors, and reporting standards are shaping the numbers as much as underlying biology. Progress is real but uneven, and the work of improving equitable access to diagnosis and care is far from finished.

March 20, 2026

Swedish Nationwide Population Study: Newborn Seizures Double Risk of ADHD

The first few weeks of life are the time when babies are most vulnerable to seizures (known as neonatal seizures). This is partly because of events that can occur during birth, and partly because the newborn brain is naturally in a more excitable state than a mature brain, making it more prone to seizure activity. 

Seizures affect roughly 1 to 3 in every 1,000 full-term babies born, and the rate is considerably higher in premature babies, at around 11 to 14 per 1,000. In most cases, seizures at this age are triggered by a specific event or injury affecting the brain. In full-term newborns, the most common cause is a condition called hypoxic-ischemic encephalopathy (HIE), which occurs when the brain is deprived of adequate oxygen and blood flow around the time of birth. Other causes include genetic or metabolic conditions, stroke, bleeding in the brain, and structural abnormalities in how the brain developed. In very premature babies, bleeding into the fluid-filled spaces of the brain (known as intraventricular hemorrhage) is the leading culprit. 

Diagnosing seizures in newborns is tricky because many normal or abnormal movements and behaviors in this age group can look like seizures without actually being them. For this reason, monitoring the baby’s brain activity using an electroencephalogram (EEG) – a test that records electrical signals in the brain – is essential to confirm whether a seizure is truly occurring. 

Sweden’s single-payer health system provides universal coverage, with national registers linking healthcare and population data. Researchers tracked infants with EEG/aEEG-confirmed seizures born between 2009 and 2020 and compared them to controls without neonatal seizures. 

Altogether, 1062 infants with neonatal seizures were matched with 5310 controls. 

The team adjusted for birth, mode of delivery, sex, birth weight, and Apgar scores – quick, standardized assessments used to evaluate newborns’ health minutes after birth. 

With these adjustments, infants who had neonatal seizures were twice as likely to subsequently be diagnosed with ADHD and three times as likely to be subsequently diagnosed with autism spectrum disorder.  

The authors emphasized that because the study was observational, it cannot demonstrate a direct cause-and-effect relationship between neonatal seizures and outcomes. Factors like seizure frequency, genetics, and socioeconomic status are thought to significantly impact the prognosis of affected children, but these could not be included in this study due to data limitations. 

March 18, 2026

Meta-analysis Finds Small to Moderate Benefits of Single Exercise Sessions for Adult ADHD

Background: 

There are currently few long-term treatment options for adult ADHD. Psychostimulants can help reduce symptoms, but their benefits rely on availability, continued use, and are not easily tolerated by some. Cognitive-behavioral therapies have also proven to be helpful, but access is limited because they must be provided by trained specialists. These challenges highlight the need to explore alternative interventions that could provide cognitive and behavioral improvements with fewer side effects. 

Exercise has shown potential as a nonclinical intervention for ADHD. Previous research indicates that physical activity can increase cortical volume, enhance brain activation, and boost connectivity in cognitive regions, as well as raise dopamine and norepinephrine levels – effects similar to psychostimulants. Research in children and teens with ADHD has found that both regular exercise programs and even single workout sessions can improve executive functions (mental skills like planning and self-control) and reduce core ADHD symptoms. But whether exercise helps adults with ADHD has remained an open question. 

Study:

A Chinese sports medicine research team set out to answer this by reviewing all available peer-reviewed studies on exercise and adult ADHD. They found so few studies on regular exercise programs – only four total, and three of those were small pilot studies just testing whether the approach was feasible – that they couldn’t draw firm conclusions about long-term exercise interventions. 

However, they were able to analyze four moderate-to-high-quality studies involving 152 adults with ADHD that tested single exercise sessions. The combined results showed moderate improvements in inhibitory control (the ability to resist impulses and stay focused). Adults not taking medication showed large improvements.  

When they looked at four studies involving 170 adults, they found small but consistent improvements in core ADHD symptoms after single exercise sessions. There was little to no variation (heterogeneity) in individual study outcomes, and no sign of publication bias. 

Results:

The team concluded, “Overall, these findings offer preliminary evidence on the potential role of exercise as a helpful strategy in the management of adult ADHD,” but cautioned that more well-designed randomized controlled trials are needed to determine the efficacy of both acute and chronic exercise interventions for adult ADHD, with particular emphasis placed on determining the best “prescription” for exercise – what type, how intense, and how often. 

They also noted that most existing research has focused narrowly on attention and impulse control, while other important mental abilities like working memory and mental flexibility remain largely unexplored. 

Take-Away

The takeaway here is practical and accessible: you don't need a long-term fitness program to get a cognitive bump from exercise if you have ADHD. Even a single session appears to help — particularly with impulse control. While the research base is still thin and we don't yet know the ideal exercise "prescription," the risk-benefit calculation is hard to argue with. For adults with ADHD who can't access medication or therapy, or who simply want an additional tool, breaking a sweat may be worth building into the routine.