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

Evidence-Based Interventions for ADHD

EBI-ADHD: 

If you live with ADHD, treat ADHD, or write about ADHD, you’ve probably run into the same problem: there’s a ton of research on treatments, but it’s scattered across hundreds of papers that don’t talk to each other.  The EBI-ADHD website fixes that. 

EBI-ADHD (Evidence-Based Interventions for ADHD) is a free, interactive platform that pulls together the best available research on how ADHD treatments work and how safe they are. It’s built for clinicians, people with ADHD and their families, and guideline developers who need clear, comparable information rather than a pile of PDFs. EBI-ADHD Database  The site is powered by 200+ meta-analyses covering 50,000+ participants and more than 30 different interventions.  These include medications, psychological therapies, brain-stimulation approaches, and lifestyle or “complementary” options. 

The heart of the site is an interactive dashboard.  You can: 

  1. Choose an age group: children (6–17), adolescents (13–17), or adults (18+). 
  1. Choose a time frame: results at 12, 26, or 52 weeks. 
  1. Choose whether to explore by intervention (e.g., methylphenidate, CBT, mindfulness, diet, neurofeedback) or by outcome (e.g., ADHD symptoms, functioning, adverse events), depending on what’s available. EBI-ADHD Database 

The dashboard then shows an evidence matrix: a table where each cell is a specific treatment–outcome–time-point combination. Each cell tells you two things at a glance: 

  1. How big the effect is, compared to placebo or another control (large benefit, small benefit, no effect, small negative impact, large negative impact). 
  1. How confident we can be in that result (high, moderate, low, or very low certainty).  

Clicking a cell opens more detail: effect sizes, the underlying meta-analysis, and how the certainty rating was decided. 

EBI-ADHD is not just a curated list of papers. It’s built on a formal umbrella review of ADHD interventions, published in The BMJ in 2025. That review re-analyzed 221 meta-analyses using a standardized statistical pipeline and rating system. 

The platform was co-created with 100+ clinicians and 100+ people with lived ADHD experience from around 30 countries and follows the broader U-REACH framework for turning complex evidence into accessible digital tools.  

Why it Matters 

ADHD is one of the most studied conditions in mental health, yet decisions in everyday practice are still often driven by habit, marketing, or selective reading of the literature. EBI-ADHD offers something different: a transparent, continuously updated map of what we actually know about ADHD treatments and how sure we are about it. 

In short, it’s a tool to move conversations about ADHD care from “I heard this works” to “Here’s what the best current evidence shows, and let’s decide together what matters most for you.” 

Meta-analysis Finds Tenuous Links Between ADHD and Thyroid Hormone Dysregulation

The Background:

Meta-analyses have previously suggested a link between maternal thyroid dysfunction and neurodevelopmental disorders (NDDs) in children, though some studies report no significant difference. Overweight and obesity are more common in children and adolescents with NDDs. Hypothyroidism is often associated with obesity, which may result from reduced energy expenditure or disrupted hormone signaling affecting growth and appetite. These hormone-related parameters could potentially serve as biomarkers for NDDs; however, research findings on these indicators vary. 

The Study:

A Chinese research group recently released a meta-analysis examining the relationship between neurodevelopmental disorders (NDDs) and hormone levels – including thyroid, growth, and appetite hormones – in children and adolescents.  

The analysis included peer-reviewed studies that compared hormone levels – such as thyroid hormones (FT3, FT4, TT3, TT4, TSH, TPO-Ab, or TG-Ab), growth hormones (IGF-1 or IGFBP-3), and appetite-related hormones (leptin, ghrelin, or adiponectin) – in children and adolescents with NDDs like ADHD, against matched healthy controls. To be included, NDD cases had to be first-diagnosis and medication-free, or have stopped medication before testing. Hormone measurements needed to come from blood, urine, or cerebrospinal fluid samples, and all studies were required to provide both means and standard deviations for these measurements. 

Meta-analysis of nine studies encompassing over 5,700 participants reported a medium effect size increase in free triiodothyronine (FT3) in children and adolescents with ADHD relative to healthy controls. There was no indication of publication bias, but variation between individual study outcomes (heterogeneity) was very high. Further analysis showed FT3 was only significantly elevated in the predominantly inattentive form of ADHD (three studies), again with medium effect size, but not in the hyperactive/impulsive and combined forms

Meta-analysis of two studies combining more than 4,800 participants found a small effect size increase in thyroid peroxidase antibody (TPO-Ab) in children and adolescents with ADHD relative to healthy controls. In this case, the two studies had consistent results. Because only two studies were involved, there was no way to evaluate publication bias. 

The remaining thyroid hormone meta-analyses, involving 6 to 18 studies and over 5,000 participants in each instance, found no significant differences in levels between children and adolescents with ADHD and healthy controls

Meta-analyses of six studies with 317 participants and two studies with 192 participants found no significant differences in growth hormone levels between children and adolescents with ADHD and healthy controls. 

Finally, meta-analyses of nine studies with 333 participants, five studies with 311 participants, and three studies with 143 participants found no significant differences in appetite-related hormone levels between children and adolescents with ADHD and healthy controls. 

The Conclusion:

The team concluded that FT3 and TPO-Ab might be useful biomarkers for predicting ADHD in youth. However, since FT3 was only linked to inattentive ADHD, and TPO-Ab’s evidence came from just two studies with small effects, this conclusion may overstate the meta-analysis results. 

Our Take-Away:

Overall, this meta-analysis found only limited evidence that hormone differences are linked to ADHD. One thyroid hormone (FT3) was higher in children with ADHD—mainly in the inattentive presentation—but the findings varied widely across studies. Another marker, TPO-Ab, showed a small increase, but this came from only two studies, making the result less certain. For all other thyroid, growth, and appetite-related hormones, the researchers found no meaningful differences between children with ADHD and those without. While FT3 and TPO-Ab may be worth exploring in future research, the current evidence is not strong enough to consider them reliable biomarkers.

 

December 15, 2025

Meta-analysis Finds Assisted Reproductive Techniques Associated with Offspring ADHD

Meta-analysis Finds Assisted Reproductive Techniques Associated with Offspring ADHD 

Background:

Recent progress in reproductive medicine has increased the number of children conceived via assisted reproductive techniques (ART). These include: 

  • In vitro fertilization (IVF), in which eggs are retrieved from the ovaries and fertilized with sperm in a laboratory; embryos are then transferred into the uterus.  
  • Intracytoplasmic sperm injection (ICSI), where a single sperm is injected directly into an egg. 
  • Intrauterine insemination (IUI), in which sperm is placed directly into the uterus around the time of ovulation. This is often combined with ovulation-inducing (OI) medications. 

Although ART helps with infertility, there are concerns about its long-term effects on offspring, especially regarding neurodevelopment. Factors such as hormonal treatments, gamete manipulation, altered embryonic environments, as well as parental age and infertility, may influence brain development and raise the risk of neurodevelopmental and mental health disorders. 

With previous studies finding conflicting results on a possible association between ART and increased risk of mental health disorders, an Indian research team has just published a new meta-analysis exploring this topic. 

The Study:

Studies were eligible if they were observational (cohort, case-control, or cross-sectional), reported confounder-adjusted effect sizes for ADHD, and were published in English in peer-reviewed journals. 

A meta-analysis of eight studies encompassing nearly twelve million individuals indicated a 7% higher prevalence of ADHD in offspring conceived via IVF/ICSI compared to those conceived naturally. The heterogeneity among studies was minimal, and no evidence of publication bias was observed. 

The study’s 95% confidence interval ranged from 4% to 10%. Further analysis of five studies comprising almost nine million participants that distinguished outcomes by sex revealed that the increase in ADHD risk among female offspring was not statistically significant. In contrast, the elevated risk in male offspring persisted, though it was marginally significant, with the lower bound of the confidence limit at only 1%. 

Results:

A meta-analysis of three studies (1.4 million participants) found a 13% higher rate of ADHD in children conceived via ovulation induction/intrauterine insemination (OI/IUI) compared to natural conception. The effect size, though doubled, remains small. Minimal heterogeneity and no publication bias were observed. 

The team concluded, “The review found a small but statistically significant moderate certainty evidence of an increased risk of ADHD in those conceived through ART, compared to spontaneous conception. The magnitude of observed risk is small and is reassuring for parents and clinicians.” 

Our Take-Away:

Overall, the meta-analysis points to a small, but measurable increase in ADHD diagnoses among children conceived through ART, but the effect sizes are modest and supported by moderate-certainty evidence. And we must always keep in mind that the researchers who wrote the original articles could not correct for all possible confounds.  These findings suggest that while reproductive technologies may introduce slight variation in neurodevelopmental outcomes, the effects are small and uncertain. For families and clinicians, the results are generally reassuring: ART remains a safe and effective avenue to parenthood, and the results of this study should not be viewed as a prohibitive concern. Thoughtful developmental monitoring and open, evidence-based counseling can help ensure that ART-conceived children receive support that caters to their individual needs.

 

December 12, 2025