October 29, 2024

Updated Analysis of ADHD Prevalence in the United States: 2018-2021

Attention-Deficit/Hyperactivity Disorder (ADHD) remains a prevalent condition among children and adolescents in the United States. A recent analysis based on the National Health Interview Survey (NHIS), conducted by the National Center for Health Statistics at the CDC, provides an updated look at ADHD prevalence from 2018 to 2021. Here’s a closer look at what the data reveals.

How the Survey Works

The NHIS is an annual survey primarily conducted through face-to-face interviews in respondents’ homes. Telephone interviews are used as a substitute in cases where travel is impractical. For each family interviewed, one child aged 3-17 is randomly selected for the survey through a computer program. Over the four years studied (2018-2021), a total of 26,422 households with children or adolescents participated.

Overall ADHD Prevalence and Age-Related Trends

The analysis found that 9.5% of children and adolescents in the United States had been diagnosed with ADHD, based on reports from family members. However, the prevalence varied significantly with age:

  • Ages 3-5: 1.5%
  • Ages 6-11: 9.6%
  • Ages 12-17: 13.4%

The increase in ADHD diagnosis with age underscores the importance of monitoring children’s developmental needs as they progress through school and adolescence.

Gender Differences: Higher Rates Among Males

The survey revealed a notable difference in ADHD prevalence between genders, with 12.4% of males diagnosed compared to 6.6% of females—nearly a two-to-one gap. This aligns with previous research indicating that ADHD is more frequently diagnosed in boys than girls, though awareness of how ADHD presents differently across genders is growing.

Family Income and ADHD Rates

Family income played a significant role in ADHD prevalence, particularly among lower-income groups:

  • Below the poverty line: 12.7%
  • Above the poverty line but less than twice that level: 10.3%
  • Above twice the poverty level: 8.5%

This pattern suggests that socioeconomic factors might influence the diagnosis and management of ADHD, with lower-income families possibly experiencing greater barriers to early diagnosis or consistent treatment.

Regional Differences Across the U.S.

Geographic location also impacted ADHD rates. Prevalence was highest in the South (11.3%), followed by the Midwest (10%), the Northeast (9.1%), and significantly lower in the West (6.9%). These variations could reflect regional differences in healthcare access, diagnostic practices, or cultural attitudes towards ADHD.

Stability Over Time

Despite these variations in demographics, the overall prevalence of ADHD remained relatively stable across the study period from 2018 to 2021, showing no significant changes by year.

What This Means for Families and Healthcare Providers

The findings from this updated analysis provide a clearer picture of ADHD’s prevalence across different demographic groups in the United States. They highlight the need for tailored approaches to diagnosis and care, taking into account factors like age, gender, income, and geographic location. With ADHD being a common condition affecting nearly 1 in 10 children, ongoing research and support for families are crucial to ensure that those with ADHD receive the care and resources they need.

Conclusion: 

This study reinforces the importance of awareness and early intervention, especially for families in underserved regions or those facing economic challenges. As clinicians and educators continue to support children with ADHD, understanding these demographic trends can help in creating more equitable access to diagnosis and treatment.

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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Inequities in ADHD diagnosis in the United States

Inequities in ADHD diagnosis in the United States

A transcontinental study team (California, Texas, Florida) used a nationally representative sample – the 2018 National Survey of Children’s Health – to query 26,205 caregivers of youth aged 3 to 17 years old to explore inequities in ADHD diagnosis.  

With increasing accessibility of the internet in the U.S., more than 80% of adults now search for health information online. Recognizing that search engine data could help clarify patterns of inequity, the team also consulted Google Trends.

The team noted at the outset that “[d]ocumenting the true prevalence of ADHD remains challenging in light of problems of overdiagnosis (e.g., following quick screening rather than full evaluation incorporating multi-informant and multi-method data given limited resources) and underdiagnosis (e.g., reflecting inequities in healthcare and education systems).” Underdiagnosis is known to be influenced by lack or inadequacy of health insurance, inadequate public health funding, stigma, sociocultural expectations in some ethnic groups, and structural racism, among other factors.

After controlling for poverty status, highest education in household, child’s sex, and child’s age, the team reported that Black youth were a quarter (22%) less likely to receive ADHD diagnoses than their white peers. Latino/Hispanic youth were a third (32%) less likely and Asian youth three-quarters (73%) less likely to receive ADHD diagnoses than their white peers.

The team also found that state-level online search interest in ADHD was positively associated with ADHD diagnoses, after controlling for race/ethnicity, poverty status, highest education in household, child’s sex, and child’s age. However, the odds ratio was low (1.01), “suggesting the need for additional evaluation.” Furthermore, “There was no interaction between individual-level racial/ethnic background and state-level information-seeking patterns. … the state-level online information-seeking variation did not affect the odds that youth of color would have a current ADHD diagnosis over and above other included characteristics.” 

That could be due in part to the gap in high-speed broadband access between Black and Hispanic in contrast to white populations, but that would not explain the even larger gaps in diagnosis for Asian youth, who tend to come from more prosperous backgrounds.

The team concluded, “Persistent racial/ethnic inequities warrant systematic changes in policy and clinical care that can attend to the needs of underserved communities. The digital divide adds complexity to persistent racial/ethnic and socioeconomic inequities in ADHD diagnosis …”

Variations in Diagnosis

Variations in Diagnosis

A cohort study looked at over five million adults, and over 850,000 children between the ages of five and eleven, who received care at Kaiser Permanente Northern California during the ten-year period from the beginning of 2007 through the end of 2016. At any given time, KPNC serves roughly four million persons. It is representative of the population of the region, except for the highest and lowest income strata.

Among adults rates of ADHD diagnosis rose from 0.43% to 0.96%. Among children the diagnosis rates rose from 2.96% to 3.74%, ending up almost four times as high as for adults.

Non-Hispanic whites had the highest adult rates throughout, increasing from 0.67% in 2007 to 1.42% in 2016. American Indian or Alaska Native (AIAN) had the second highest rates, rising from 0.56% to 1.14%. Blacks and Hispanics had roughly comparable rates of diagnosis, the former rising from 0.22% to 0.69%, the latter from 0.25% to 0.65%. The lowest rates were among Asians (rising from 0.11% to 0.35%) and Native Hawaiian or other Pacific Islanders (increasing from 0.11% to 0.39%).

Odds of diagnosis dropped steeply with age among adults. Relative to 18-24-year-olds, 25-34-year-olds were 1/6th less likely to be diagnosed with ADHD, 35-44-year-olds 1/3rd less likely, 45-54-year-olds less than half as likely, 55-64-year-olds less than a quarter as likely, and those over 65 about a twentieth as likely. This is consistent with other studies reporting and age dependent decline in the diagnosis.

Adults with the highest levels of education were twice as likely to be diagnosed as those with the lowest levels. But variations in median household income had almost no effect. Women were marginally less likely to be diagnosed than men.

ADHD is associated with some other psychiatric disorders. Compared with normally developing adults, and adjusted for confounders, those with ADHD were five times as likely to have an eating disorder, over four times as likely to be diagnosed with bipolar disorder or depression, more than twice as likely to suffer from anxiety, but only slightly more likely to abuse drugs or alcohol.

The authors speculate that rising rates of diagnosis could reflect increasing recognition of ADHD in adults by physicians and other clinicians as well as growing public awareness of ADHD during the decade under study. Turning to the strong differences among ethnicities, they note, Racial/ethnic differences could also reflect differential rates of treatment seeking or access to care. Racial/ethnic background is known to play an important role in opinions on mental health services, health care utilization, and physician preferences. In addition, rates of diagnosis- seeking to obtain stimulant medication for nonmedical use may be more common among white vs nonwhite patients. They conclude, greater consideration must be placed on cultural influences on health care seeking and delivery, along with an increased understanding of the various social, psychological, and biological differences among races/ethnicities as well as culturally sensitive approaches to identify and treat ADHD in the total population.

But the main take home message of this work is that most cases of ADHD in adults are not being diagnosed by clinicians. We know from population studies, worldwide, that about three percent of adults suffer from the disorder. This study found that less than 1 percent are diagnosed by their doctors. Clearly, more education is needed to teach clinicians how to identify, diagnose and treat ADHD in adults.

December 18, 2023

Addressing the challenge of under-diagnosed adult ADHD

Addressing the challenge of under-diagnosed adult ADHD

There is a well-documented gap between the known prevalence of adult ADHD and rates of diagnosis and treatment. In Germany, epidemiological studies of nationally representative community samples have found prevalence rates ranging from 3.1% to 4.7%. Yet, studies of publicly insured individuals aged 18 to 69 years old report rates of diagnosed ADHD between 0.04% and 0.4%. So, even in a country with universal health insurance, more than nine out of ten adults with ADHD go undiagnosed.

Many factors contribute to under-diagnosis: stigma, culturally influenced perceptions, and lack of motivation by those affected. Another crucial factor is the lack of recognition of ADHD symptoms by clinicians.

A research team surveyed 144 psychologists, 32 physicians, and two occupational therapists. Almost three in five participants were psychotherapists, a quarter were neuropsychologists, and one in seven were psychiatrists.

Four out of five clinicians stated they had received only a few hours of ADHD-specific training. One in four stated they had not examined guidelines for diagnosing ADHD. A lack of formal training among the vast majority, and unfamiliarity with current diagnostic guidelines in a significant minority, were surprising findings among clinicians who regularly work with adults with ADHD.

Many clinicians had difficulty identifying core features of adult ADHD as defined by the DSM-5 and International Classification of Diseases, Tenth Revision (ICD-10). Roughly one in five stated that hyperactivity had little relevance to adult ADHD. The only core feature correctly identified by more than half the respondents was having difficulties concentrating. Impairments in social behavior or aggression and memory impairment were not identified as being clearly relevant or irrelevant to adult ADHD.

The authors concluded that these findings appear to indicate some uncertainty or at least a lack of consensus among clinicians about what symptoms are relevant to ADHD in adulthood, and it is likely that this uncertainty contributes to diagnostic inaccuracy.

Most respondents reported using self-report scales of ADHD symptoms and using unstructured interviews. While slightly more than half agreed that collateral reports are important to diagnosis, only about a third reported regularly using them. This is a problem given the limited accuracy of self-reported childhood symptoms for documenting the childhood-onset of the disorder. Semi-structured interviews are also known to improve the accuracy of diagnosis, but are rarely used in clinical practice.

Over half of psychologists and a quarter of physicians reported using cognitive or neuropsychological testing, even though this is at variance with German (and other) guidelines, which specify that such testing is suitable for clarifying strengths and weaknesses, but not for ruling out or confirming a diagnosis of ADHD. The European Consensus Statement also states that cognitive/neuropsychological testing should only be used as a secondary or supplementary assessment tool.

While three out of four clinicians recommended stimulant drug treatment, psychologists tended to be more hesitant to do so. This is likely because German psychologists receive little training in pharmacotherapy, and do not have prescription privileges. Given the demonstrated efficacy of stimulant treatment, this points to a need to better educate psychologists in this regard.

Almost three in four respondents cited a lack of clinician knowledge and experience as a barrier to ADHD diagnosis. Most clinicians also stated they were either uncertain or only somewhat certain of their ability to diagnose ADHD. That suggests that more extensive ADHD-specific training is needed.

A limitation of the survey was the relatively low participation by physicians. It is also likely that the findings are not reflective of practices in ADHD specialty clinics.

The authors concluded, Further training is needed to improve clinicians' understanding of ADHD in adulthood and to align diagnostic practices with guideline recommendations. Whereas discrepancies between respondents regarding the relative importance of peripheral symptoms (e.g., memory problems) were most common, a lack of consensus was found even for core symptoms listed by diagnostic criteria. Particularly among psychologists improved awareness regarding the benefits of stimulant medications is needed to bring their treatment recommendations in line with evidence-based guidelines.

September 22, 2023

Updated Analysis of ADHD Prevalence in the United States: 2018-2021

Attention-Deficit/Hyperactivity Disorder (ADHD) remains a prevalent condition among children and adolescents in the United States. A recent analysis based on the National Health Interview Survey (NHIS), conducted by the National Center for Health Statistics at the CDC, provides an updated look at ADHD prevalence from 2018 to 2021. Here’s a closer look at what the data reveals.

How the Survey Works

The NHIS is an annual survey primarily conducted through face-to-face interviews in respondents’ homes. Telephone interviews are used as a substitute in cases where travel is impractical. For each family interviewed, one child aged 3-17 is randomly selected for the survey through a computer program. Over the four years studied (2018-2021), a total of 26,422 households with children or adolescents participated.

Overall ADHD Prevalence and Age-Related Trends

The analysis found that 9.5% of children and adolescents in the United States had been diagnosed with ADHD, based on reports from family members. However, the prevalence varied significantly with age:

  • Ages 3-5: 1.5%
  • Ages 6-11: 9.6%
  • Ages 12-17: 13.4%

The increase in ADHD diagnosis with age underscores the importance of monitoring children’s developmental needs as they progress through school and adolescence.

Gender Differences: Higher Rates Among Males

The survey revealed a notable difference in ADHD prevalence between genders, with 12.4% of males diagnosed compared to 6.6% of females—nearly a two-to-one gap. This aligns with previous research indicating that ADHD is more frequently diagnosed in boys than girls, though awareness of how ADHD presents differently across genders is growing.

Family Income and ADHD Rates

Family income played a significant role in ADHD prevalence, particularly among lower-income groups:

  • Below the poverty line: 12.7%
  • Above the poverty line but less than twice that level: 10.3%
  • Above twice the poverty level: 8.5%

This pattern suggests that socioeconomic factors might influence the diagnosis and management of ADHD, with lower-income families possibly experiencing greater barriers to early diagnosis or consistent treatment.

Regional Differences Across the U.S.

Geographic location also impacted ADHD rates. Prevalence was highest in the South (11.3%), followed by the Midwest (10%), the Northeast (9.1%), and significantly lower in the West (6.9%). These variations could reflect regional differences in healthcare access, diagnostic practices, or cultural attitudes towards ADHD.

Stability Over Time

Despite these variations in demographics, the overall prevalence of ADHD remained relatively stable across the study period from 2018 to 2021, showing no significant changes by year.

What This Means for Families and Healthcare Providers

The findings from this updated analysis provide a clearer picture of ADHD’s prevalence across different demographic groups in the United States. They highlight the need for tailored approaches to diagnosis and care, taking into account factors like age, gender, income, and geographic location. With ADHD being a common condition affecting nearly 1 in 10 children, ongoing research and support for families are crucial to ensure that those with ADHD receive the care and resources they need.

Conclusion: 

This study reinforces the importance of awareness and early intervention, especially for families in underserved regions or those facing economic challenges. As clinicians and educators continue to support children with ADHD, understanding these demographic trends can help in creating more equitable access to diagnosis and treatment.

October 29, 2024

Meta-Analysis Shows No Significant Impact of Caffeine on ADHD Symptoms

Stimulant medications like methylphenidate and amphetamines are well-established treatments for reducing ADHD symptoms, making a notable difference in focus and behavior. Given that caffeine is also a stimulant, researchers have wondered whether it might offer similar benefits for managing ADHD symptoms. A recent meta-analysis conducted by a Brazilian research team sought to explore this question.

The Search for Evidence: A Limited Pool of Studies

The researchers faced an immediate challenge: there is surprisingly little research directly investigating caffeine's effects on ADHD symptoms. After a thorough review of peer-reviewed literature, they identified only four randomized controlled trials (RCTs) suitable for their analysis, encompassing a combined total of just 152 participants.

The limited number of studies—and participants—meant that the meta-analysis was not as robust as the research team might have hoped. However, they proceeded to examine the available data to determine whether caffeine showed any measurable benefit over a placebo.

Findings: Minimal Impact, No Statistical Significance

The results of the meta-analysis showed a slight decrease in ADHD symptoms among those who consumed caffeine compared to those given a placebo. However, this reduction was not statistically significant. The small sample size likely played a role in this outcome, making the study underpowered. Even if future studies with larger groups of participants were to show statistical significance, the observed effect size would likely remain too small to be clinically meaningful.

Interestingly, the four trials included in the meta-analysis showed very little variation in their findings. Each study slightly favored caffeine over placebo, but none came close to achieving statistical significance.

Conclusion: Caffeine Is Not a Substitute for ADHD Medications

Ultimately, the researchers concluded that “overall, the totality of the evidence suggests no significant benefit of caffeine over placebo in the treatment of children with ADHD.” The findings indicate that while caffeine might produce a slight reduction in symptoms, it is not an effective alternative to established ADHD treatments like methylphenidate or amphetamines.

This study highlights the importance of relying on proven medications for ADHD management rather than seeking alternatives that lack substantial evidence. While caffeine might offer a slight stimulant effect, it falls short of delivering the therapeutic benefits needed for those with ADHD to manage their symptoms effectively. For clinicians, parents, and individuals with ADHD, these results underscore the value of evidence-based treatments in improving quality of life and daily functioning.

October 28, 2024

ADHD’s Impact on Criminal Convictions—and How Medication Reduces Risk

Swedish Study Reveals ADHD’s Impact on Criminal Convictions—and How Medication Reduces Risk

ADHD has long been associated with higher rates of criminal behavior, but most studies have relied heavily on self-reported data and small, non-representative samples. A new Swedish study addresses these limitations, providing a more comprehensive and reliable picture using data from nationwide registers. It sheds light on the role of ADHD medication in reducing the risk of criminal convictions, offering insights for clinicians, policymakers, and families.

Previous Research: The Denmark Comparison

Earlier research, such as a 2019 Danish study, found that ADHD diagnosed in children and adolescents ages 4 to 15 was associated with a 1.6-fold increased risk of future criminal conviction. However, these findings were limited by a smaller sample size and a focus on just one nation’s context. Like Denmark, Sweden’s single-payer universal healthcare system allows for the collection of extensive data on health and crime records, providing an ideal environment for large-scale, population-based research.

Swedish Study Design: A Robust Approach

To investigate ADHD’s connection to criminal behavior, the Swedish research team analyzed records from a cohort of 1,646,645 individuals born between 1986 and 1997. They excluded those who died or emigrated before age 15 (the age of criminal responsibility in Sweden) and those who immigrated to Sweden, resulting in a final study group of 1,235,939 individuals. Slightly more than half of the cohort was male.

ADHD diagnoses were based on clinical records and prescriptions for approved ADHD medications, while criminal convictions—both violent and nonviolent—were identified using Sweden’s National Crime Register, covering the years 2001 to 2013. The study adjusted for various potential confounding factors, including sex, birth year, parental education, and other psychiatric conditions. They also used the Swedish Multi-Generation Register to control for unmeasured familial factors to compare outcomes among full siblings.

Key Findings: ADHD and Criminality

The study found that ADHD is strongly associated with increased rates of criminal convictions. Compared to individuals without ADHD, those with an ADHD diagnosis were roughly:

  • Four times more likely to be convicted of a violent crime.
  • Twice as likely to be convicted of a nonviolent crime.

Interestingly, when comparing conviction rates among males and females with ADHD, the rates of nonviolent convictions were similar, but females with ADHD were about 25% more likely to be convicted of a violent crime than males with ADHD.

The Role of Medication: A Significant Moderating Factor

The research also highlighted the importance of ADHD medication in reducing criminal behavior. When individuals with ADHD who were taking medication were excluded from the analysis, the data showed significantly higher rates of criminal convictions:

  • Unmedicated males with ADHD had a 50% higher rate of violent convictions and more than double the rate of nonviolent convictions compared to their typically developing peers.
  • Unmedicated females with ADHD faced even greater risks, with nearly triple the rate of violent convictions and quadruple the rate of nonviolent convictions.

These findings suggest that ADHD medications can significantly reduce the risk of both violent and nonviolent criminal behavior in individuals with ADHD, emphasizing the value of pharmacological treatment for those with the condition.

Clinical Implications: Medication as a Risk-Reducing Strategy

The researchers concluded that “ADHD is a strong risk factor for both violent and non‐violent criminal convictions in males and females even after adjustments for psychiatric comorbidities and unmeasured familial factors.” The study also found that untreated ADHD poses a particularly high risk for criminal behavior, highlighting the protective role of medication.

These findings are clinically relevant for several reasons. First, they reinforce the importance of ensuring that individuals with ADHD have access to effective treatment options, especially during the transition from adolescence into adulthood, which is statistically a period of higher risk for criminal behavior. Additionally, the study provides critical data for shaping public policy and interventions aimed at supporting individuals with ADHD, with a focus on reducing criminality through proper management of the disorder.

Conclusion:

This study offers new insights into the complex relationship between ADHD, medication, and criminal behavior, emphasizing the crucial role of treatment in mitigating risks. It provides a compelling case for prioritizing access to ADHD medication as part of a broader strategy for supporting those with ADHD.