March 7, 2025

Updated Analysis of ADHD Prevalence in The United States

The National Health Interview Survey (NHIS) is conducted annually by the National Center for Health Statistics at the Centers for Disease Control and Prevention. The NHIS is done primarily through face-to-face computer-assisted interviews in the homes of respondents. But telephone interviews are substituted on request, or where travel distances make in-home visits impractical.  

For each interviewed family, only one sample child is randomly selected by a computer program.  

The total number of households with a child or adolescent aged 3-17 for the years 2018 through 2021 was 26,422. 

Based on responses from family members, 9.5% of the children and adolescents randomly surveyed throughout the United States had ADHD.  

This proportion varied significantly based on age, rising from 1.5% for ages 3-5 to 9.6% for ages 6-11 and to 13.4% for ages 12-17. 

There was an almost two-to-one gap between the 12.4% prevalence among males and the 6.6% prevalence among females. 

There was significant variation by race/ethnicity. While rates among non-Hispanic whites (11.1%) and non-Hispanic blacks (10.5%) did not differ significantly, these two groups differed significantly from Hispanics (7.2%) and Others (6.6%). 

There were no significant variations in ADHD prevalence based on highest education level of family members. 

But family income had a significant relationship with ADHD prevalence, especially at lower incomes. For family incomes under the poverty line, the prevalence was 12.7%. That dropped to 10.3% for family incomes above the poverty level but less than twice that level. For all others it dropped further to about 8.5%. Although that might seem like poverty causes ADHD, we cannot draw that conclusion.  Other data indicate that adults with ADHD have lower incomes.  That would lead to more ADHD in kids from lower income families.

There was also significant geographic variation in reported prevalence rates. It was highest in the South, at 11.3%, then the Midwest at 10%, the Northeast at 9.1%, with a jump down to 6.9% in the West. 

Overall ADHD prevalence did not vary significantly by year over the four years covered by this study. 

Study Conclusion:

This study highlights a consistently high prevalence of developmental disabilities among U.S. children and adolescents, with notable increases in other developmental delays and co-occurring learning and intellectual disabilities from 2018 to 2021. While the overall prevalence remained stable, these findings emphasize the need for continued research into potential risk factors and targeted interventions to address developmental challenges in youth.

It is also important to note that this study assessed the prevalence of ADHD being diagnosed by healthcare professionals.  Due to variations in healthcare accessibility across the country, the true prevalence of ADHD may differ still.

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Are you struggling to get the care you need to manage your ADHD? Support The ADHD Evidence Project and get this step-by-step guide to getting the treatment you deserve: https://bit.ly/41gIQE9

Qian Li, Yanmei Li, Juan Zheng, Xiaofang Yan, Jitian Huang, Yingxia Xu, Xia Zeng, Tianran Shen, Xiaohui Xing, Qingsong Chen, and Wenhan Yang, “Prevalence and trends of developmental disabilities among US children and adolescents aged 3 to 17 years, 2018–2021,” Scientific Reports (2023) 13: 17254, https://doi.org/10.1038/s41598-023-44472-1

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Update: New Research about ADHD in Adults

Update: New Research about ADHD in Adults

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition that is typically diagnosed in childhood but can persist into adulthood. Its symptoms include inattention, hyperactivity, and impulsivity, and it can significantly affect daily life, academic achievement, and professional success. As scientific understanding of the condition continues to evolve, new research is revealing more insights into the prevalence, comorbidity, treatment, and physiological aspects of ADHD in adults. Here's a roundup of some recent findings:

Location of Mental Healthcare and ADHD Treatment Prevalence

A recent study assessing the prevalence of treatment for ADHD among US college students found that the location of mental health care significantly affects treatment outcomes. Specifically, students receiving mental healthcare on campus were less likely to receive any medication or therapy for ADHD, suggesting the need to evaluate the quality of mental health services available on college campuses and their effectiveness in treating ADHD.

 Oxidative Stress and l-Arginine/Nitric Oxide Pathway in ADHD 

Another study found a correlation between ADHD and the l-Arginine/Nitric oxide (Arg/NO) pathway, a physiological process linked to dopamine release and cardiovascular functioning. The study found that adults with ADHD who were not treated with methylphenidate (a common ADHD medication) showed variations in the Arg/NO pathway. This could have implications for monitoring potential cardiovascular side effects of ADHD medications, as well as for understanding the biochemical changes that occur in ADHD. 

Chronic Pain in ADHD

ADHD and chronic pain appear to be related, according to a comparative study of clinical and general population samples. Particularly in females with ADHD, the prevalence of chronic and multisite pain was found to be high. This calls for longitudinal studies to understand the complex sex differences of comorbid chronic pain and ADHD in adolescents and the potential impacts of stimulant use on pain.

ADHD and Violent Behavior

Finally, a study investigated the comorbidity of ADHD and bipolar disorder (BD) and its potential link to violent behavior. The research revealed a positive effect of ADHD symptoms on violence tendency and aggression scores. Moreover, male gender and young age were also found to have significant positive effects on violence and aggression scores, suggesting an association between these disorders and violent behavior.

June 3, 2024

New Zealand national birth cohort finds young adults with ADHD overrepresented at all stages of the criminal justice system

National Birth Cohort Finds Young Adults with ADHD Over-represented in Criminal Justice System

Using Statistics New Zealand’s Integrated Data Infrastructure (IDI), a large database of linked de-identified administrative and survey data about people and households, a local study team examined a three-year birth cohort (mid-1992 through mid-1995) totaling 149,076 persons.

The team assessed the presence of ADHD within this cohort through diagnosis codes and inference from medication dispensing, where there was at least one code relating to an ADHD diagnosis in the medication datasets. This subgroup consisted of 3,975 persons.

Next, they related this information to criminal justice system interactions of increasing severity, starting with police proceedings, and continuing with court charges, court convictions, and incarcerations. These interactions were tracked during an eight-year period from participants’ 17th birthday through their 25th birthday.

In this same period the team also tracked types of offenses: against people; against property; against organizations, government, and community; and violent offenses.

In all cases, the study team adjusted for gender, ethnicity, deprivation, and area of residence as potential confounders. 

With these adjustments, young adults with ADHD were over twice as likely as their typically developing peers to be proceeded against by police, to be charged with an offense, and to be convicted. They were almost five times as likely to be incarcerated. 

With the same adjustments, young adults with ADHD were over twice as likely as their typically developing peers to be convicted of offenses against organizations, government, and community. They were almost three times as likely to be convicted of crimes against persons, and over three and a half times more likely to be convicted of either violent offenses or offenses against property.

The authors noted, “The greater effect size for incarceration observed in our study may be due to the lack of control for comorbid conditions such as CD [conduct disorder], which are known criminogenic risk factors.” 

They also noted, “The sharp increase in the risk of incarceration observed may also signal differences in the NZ justice system’s approach to ADHD, which may be less responsive to the condition than other nations, particularly the steps in the justice system between conviction and sentence. This would suggest that the UNCRPD [United Nations Convention on the Rights of Persons with Disabilities] obligations of equal recognition before the law and the elimination of discrimination on the basis of disability are not being met for individuals with ADHD in NZ.”

They concluded, “Our findings revealed that not only were individuals with ADHD overrepresented at all stages of the CJS [criminal justice system] and offense types examined, there was also a pattern of increasing risk for CJS interactions as these individuals moved through the system. These results highlight the importance of early identification and responsivity to ADHD within the CJS and suggest that the NZ justice system may require changes to both of these areas to ensure that young individuals with ADHD receive equitable access to, and treatment within, the CJS.”

New Estimates on Worldwide Prevalence of ADHD

Meta-analysis updates estimates of adult ADHD prevalence worldwide

An international team of researchers conducted a comprehensive search of the peer-reviewed literature to perform a meta-analysis, with three aims:

1) assess the global prevalence of adult ADHD

2) explore possible associated factors

3) estimate the 2020 global population of persons with adult ADHD.

In doing so, they distinguished between studies requiring childhood-onset of ADHD to validate adult ADHD (persistent adult ADHD) and studies that make no such requirement and examine ADHD symptoms in adults regardless of previous childhood diagnosis (symptomatic adult ADHD).

The search yielded forty articles covering thirty countries. Twenty reported prevalence data on symptomatic adult ADHD, 19 on persistent adult ADHD, and one on both. Thirty-five studies were published in the last decade (2010-2019). Thirty-one included both urban and rural populations. Thirty-five had a quality score of six or above (out of ten). Twenty-five had sample sizes greater than a thousand.

Because the prevalence of ADHD is age-dependent, and different countries vary widely in the age structure of their populations, the authors adjusted country results for their structures. This allowed for meaningful global estimates of the prevalence of adult ADHD.

Twenty studies covering a total of 107,282 participants reported the prevalence of persistent adult ADHD. The pooled prevalence was 4.6%. After adjustment for the global population structure, the pooled prevalence was 2.6%, equivalent to roughly 140 million cases globally.

Twenty-one studies covering 50,098 participants reported on the prevalence of symptomatic adult ADHD. The pooled prevalence was 8.8%. After adjustment for the global population structure, the pooled prevalence was 6.7%, equivalent to roughly 366 million cases globally.

For persistent adult ADHD, adjusted prevalence declined steeply from 5% among 18- to 24-year-olds to 0.8% among those 60 and older.

For symptomatic adult ADHD, adjusted prevalence declined less steeply from 9% among 18- to 24-year-olds to 4.5% among that 60 and older.

In each case, subgroup analyses found no significant differences based on sex, urban or rural setting, diagnostic tool, DSM version, or investigation period, although pooled prevalence estimates of persistent adult ADHD from 2010 onward were almost twice the previous pooled prevalence estimates. For symptomatic adult ADHD, however, differences between WHO (World Health Organization) regions were highly significant, although the outliers(Southeast Asia at 25% and Eastern Mediterranean at 16%) were based on small samples(304 and 748 respectively).

In both cases, between-study heterogeneity was very high (over 97%). The authors noted, "the age of interviewed participants in the included studies was not unified, ranging from young adults to the elderly. Given the fact that the prevalence of adult ADHD decreases with advancing age, as revealed in previous investigations and our meta-regression, it is not surprising to observe such a diversity in the reported prevalence, and the considerable heterogeneity across included studies could not be fully ruled out by a priori selected variables, including diagnostic tool, DSM version, sex, setting, investigation period, WHO region, and WB [World Bank] region. The effects of other potential correlates of adult ADHD, such as ethnicity, were not able to be addressed due to the lack of sufficient information."

In both cases, there was also evidence of publication bias. The authors stated, "we did not try to eliminate publication bias in our analyses, because we deemed that an observed prevalence of adult ADHD that substantially differed from previous estimates was likely to have been published."

January 30, 2022

Meta-analysis of Exercise Interventions for Children and Adolescents Reports Medium-to-Large Improvements in Inhibitory Control, with Caveats

ADHD affects both individuals and society in many ways. Children and adolescents with ADHD often struggle with focusing, controlling impulses, and staying organized, which leads to problems with schoolwork, learning, and taking tests. These challenges can cause academic failure and make it harder for them to stay in school. 

ADHD symptoms often continue into adulthood, affecting jobs, relationships, and increasing risks for substance abuse and legal problems. 

Families of children and adolescents with ADHD face extra stress, with parents more likely to experience depression, anxiety, and relationship difficulties. The economic impact is also large, with billions spent each year on medical care, special education, lost productivity, and other related costs. 

Current treatments for ADHD mostly include medication, behavioral therapy, and educational support. While medications like stimulants can help control ADHD symptoms in the short term, they often cause side effects such as loss of appetite, trouble sleeping, slowed growth, cardiovascular risks, and potential substance dependence. These issues can make it hard for children and adolescents to stay on their medication, and about a third either don’t respond well or can’t tolerate the side effects. Once medication is stopped, the benefits fade quickly and do not lead to lasting improvements in executive functions (thinking skills). 

Behavioral therapy and parent training can help with behavior problems, but have limited effects on core mental skills like planning and self-control. These approaches also tend to be expensive, require a lot of support from parents and teachers, and are hard to use widely in schools and communities that lack resources.

Recently, exercise interventions have attracted growing interest as a non-pharmacological option. They provide several benefits: no drug-related side effects, easy accessibility, low cost, simple implementation in schools and communities, and enhanced physical and mental health. 

Previous meta-analyses examining how exercise interventions affect children and adolescents with ADHD have used traditional univariate models, which treat each study as if it only offers one independent effect size. In contrast, this study used multilevel meta-analysis — a more advanced statistical method modelling both between-study and within-study effects. This approach results in more accurate estimates and more dependable conclusions. 

Eligible studies were randomized controlled trials (RCTs) with usual care, no intervention, or waitlist controls, involving children and adolescents aged 5–18 diagnosed with ADHD by internationally recognized diagnostic criteria, and reporting inhibitory control outcomes. 

Eleven studies combining 512 children and adolescents met these inclusion standards. 

The analysis between experimental and control groups indicated that the exercise intervention group had significantly improved inhibitory control performance compared to the control group, with a medium-to-large effect size. There was very little variation (heterogeneity) in outcome between the studies, and no sign of publication bias.  

Within-group analyses showed that experimental groups had significant improvements after the intervention compared to baseline, with large effect sizes and moderate heterogeneity. 

By comparison, analyzing control groups over the same period revealed no significant differences, indicating that inhibitory control abilities in these groups remained largely unchanged throughout the observation period. There was little heterogeneity.  

Nevertheless, only one of the studies was rated low risk of bias, nine had some concerns, and two were rated high risk of bias. The greatest shortcomings were a lack of blinding and preregistration. 

The study authors therefore concluded that the overall evidence quality of this meta-analysis is low, limiting confidence in the results. While exercise interventions seem to improve inhibitory control abilities in children and adolescents with ADHD, significant methodological limitations create uncertainty about the effect size. These require more rigorous future studies to clarify these effects. Despite these caveats, they noted that all included studies reported statistically significant, consistent benefits from exercise interventions, offering preliminary support for their use as an adjunctive approach. 

Takeaway

This study lands in the same conversation as the adult ADHD exercise meta-analysis, and together they start to form a coherent picture: exercise appears to support attention and impulse control across the lifespan for people with ADHD, not just in one age group. The honest caveat is that the research quality in this field is still catching up to the enthusiasm — most studies have design weaknesses that limit confidence in the exact size of the effect. But the consistency of findings across studies, age groups, and now two separate meta-analyses is hard to dismiss.  

 

March 23, 2026

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 as opposed to a crisis of escalating proportions as social media may make one think. 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