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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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Methylphenidate May Reduce Risk of Burn Injury in Children with ADHD

Methylphenidate reduces risk of burn injury in children with ADHD in nationwide population cohort study

Children with ADHD are at higher risk of getting severe burns than normally-developing children. Burn injuries can be traumatic, imposing physical, psychological, and economic burdens on children, their families, and society. Methylphenidate is known to be effective in reducing ADHD symptoms. Can it also reduce the risk of burn injuries?

A team of Taiwanese researchers collaborating with two British researchers explored that question by looking at a nationwide population cohort. Taiwan has a single-payer national health insurance system that includes the entire population (99.6 percent coverage). Using Taiwan's National Health Insurance Research Database(NHIRD), they identified over 90,000 youths under 18 years old with a diagnosis of ADHD. Youths who had burned injuries before diagnosis were excluded. ADHD youths were further divided into three groups: those not prescribed methylphenidate (over 22,000), those prescribed methylphenidate for less than 90 days (over 17,500), and those prescribed methylphenidates for 90 days or more(over 50,000).

Because methylphenidate is the only approved stimulant in Taiwan, it was the only stimulant analyzed in this study. Atomoxetine, a non-stimulant, is also approved in Taiwan, but only for those whose, outcomes with methylphenidate are suboptimal. It was only used by 4 percent of those on ADHD medication, and generally after prior use of methylphenidate, so there was no way to evaluate its effectiveness. Among ADHD youths not on methylphenidate, the proportion who got burn injuries was 6.7 percent. That dropped to 4.5 percent for those medicated for under 90 days, and to 2.9 percent for those on longer-term medication.

Calculations indicated that half of all burn injuries could have been prevented if all youths had been on methylphenidate. After adjusting for multiple confounders - seizure, intellectual disability, autism, conduct disorder, opposition defiant disorder, anxiety, depression, and psychotropic use (benzodiazepine, Z-drugs, antipsychotics, and antidepressants) that taking methylphenidate for any length of time was 38 percent less likely to suffer burn injuries. Moreover, longer-term medication had a greater beneficial effect. Those taking methylphenidate for under 90 days were 30 percent less likely to get burn injuries, whereas those taking it for 90 or more days were less than half as likely to get burn injuries as those not on methylphenidate.

The authors emphasized, "This nationwide population-based study has several strengths. First, the nationally representative sample was substantial and minimized selection bias. Second, patients with ADHD were identified through physician-based diagnoses. Third, all MPH [methylphenidate] prescriptions are recorded in the NHIRD, avoiding misclassification bias. Also, by excluding burn injuries before ADHD diagnosis, the reverse causal relationship between ADHD and burn injury was eliminated."

December 6, 2023
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Sex Differences in ADHD Symptoms and Related Cognitive Deficits in Youths

Sex Differences in ADHD Symptoms and Related Cognitive Deficits in Youths

To what extent does sex matter in the expression of ADHD symptoms and associated cognitive deficits among youths with ADHD?

A recently published meta-analysis of 54 studies by a Canadian team of researchers at the University of Quebec at Montreal suggests it makes little to no difference. A meta-analysis of 26 studies with over 5,900 youths found no significant difference in inattention symptoms, and a meta-analysis of 24 studies with over 5,500 youths likewise found no difference in hyperactivity-impulsivity symptoms. Separating out hyperactivity and impulsivity made no difference.

Given these results, it's no surprise that a meta-analysis of 15 studies with over 3,500 youths again found no significant divergence between the sexes for total ADHD symptoms. Parents and teachers differed, however, in their ratings of symptoms. Whereas parents observed no differences, teachers reported boys had slightly more inattention and hyperactive-impulsive behaviors than girls. Turning to cognitive functions, a series of meta-analyses found no significant sex differences for interference control, working memory, and planning scores. But boys performed slightly worse on inhibition and motor response inhibition. While the raw data also showed boys slightly under-performing girls on cognitive flexibility, strong evidence of publication bias made this unreliable.

The team also compared youths with ADHD and youths without ADHD. Both for females and for males, those differences in ADHD symptoms were - as would be expected - extremely large, whether for total symptoms, inattention, or hyperactivity-impulsivity. All cognitive function scores were moderately better for normally developing boys compared with boys with ADHD, and for normally developing girls compared with girls with ADHD. Yet once again, when comparing these effect sizes between girls and boys, there were no significant differences for any of the symptom and cognitive function effects.

"In other words," the authors wrote, "boys and girls with ADHD presented significantly more primary symptoms and executive and attention deficits than did their peers without ADHD, and effect sizes were not significantly different between the sexes." They concluded, "girls with ADHD do not differ from boys with ADHD in many domains of cognitive functioning, and they have significantly more severe difficulties across the executive and attentional functions measured relative to girls without ADHD. This meta-analysis is the first to examine sex differences in cognitive flexibility, working memory, and planning."

December 11, 2023
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Hypertensive Disorders of Pregnancy and Offspring ADHD: An Exploration

Two nationwide population studies explore relationship between maternal hypertensive disorders of pregnancy and ADHD in offspring

Two new studies, examining entire nationwide populations on opposite sides of the world, have just reported findings on the association between hypertensive disorders of pregnancy (HDP) and subsequent ADHD in off spring. HDP includes chronic hypertension, pre-eclampsia, pre-eclampsia superimposed on chronic hypertension, and gestational hypertension.

According to the Mayo Clinic, Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, most often the liver and kidneys. Preeclampsia usually begins after 20 weeks of pregnancy in women whose blood pressure had been normal. Left untreated, it can lead to serious complications for both mother and baby and can be fatal. This range of conditions affects more than one in twenty pregnancies worldwide. HDP hampers permeability of the placenta, which may reduce delivery of blood-borne oxygen and nutrients to the fetus, potentially affecting brain development. ADHD could thus theoretically emerge as a neurodevelopmental outcome.

To what extent is this borne out in national-wide population studies? Both Taiwan and Sweden have single-payer national health insurance systems that systematically track virtually every resident. One study team used the Taiwan National Health Insurance research database to examine a cohort of 877,233 children born between 2004 and 2008. The other study team used the Swedish national registers to explore a cohort of 1,085,024 individuals born between 1987 and 1996.

The Taiwanese study adjusted for the following covariate/confounders: year of birth, fetal sex, paternal age, maternal age, family income, urbanization level, maternal diabetes diagnosis, preterm birth, small for gestational age, and parental psychiatric disorders. The Swedish study adjusted for the calendar year of birth, offspring sex, maternal age, parity, height, body mass index, smoking, presentational diabetes, parental educational level, occupation, and marital status. In the Taiwanese population, children of mothers with hypertensive disorders during pregnancy were about 20% more likely to develop ADHD than those of mothers without such disorders. There was no significant difference between chronic hypertension and pregnancy-induced hypertension/pre-eclampsia.

In the Swedish population, children of mothers with hypertensive disorders during pregnancy were about 10% more likely to develop ADHD than those of mothers without such disorders. But the Swedish study also went a step further. It is incredibly difficult to identify all significant confounding variables. But if you have a large enough study population, one can examine the effect of restricting the analysis to siblings within the same families. In that way, one can control in large measure for familial confounding “ shared environment and heredity. In the subsample of siblings “ 1,279 exposed to HDP versus 1,607 not exposed “ those exposed to outerwear were 9% more likely to develop ADHD, but this outcome was not statistically significant.

Noting the reduced statistical power of the subsample, the authors nonetheless concluded, the magnitude of these associations might be too weak(for ADHD in particular) to be considered an important risk factor at the level of the general population  Moreover, in a separate cohort of 285,901 Swedish men born between 1982 and 1992 who attended assessments for military conscription, mildly lower cognitive scores among those exposed to HDP in uteri vanished altogether (mean difference = 0) when limited to comparisons between full siblings (1,917 exposed versus 2,044 not exposed).

November 14, 2023
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ADHD symptoms and suicidal ideation in college

ADHD symptoms and suicidal ideation in college

The mechanisms underlying the association between ADHD symptoms and suicidal ideation are poorly understood. A team of researchers from France and Montreal set out to explore this relationship with 2,331 French college students.

The students were participants in the internet-based student Health Research Enterprise project, a prospective population-based cohort study of students in higher education institutions in France. The i-Share study includes a longitudinal collection of data on childhood and family history, lifestyle, health information, and psychosocial examinations during the college years and beyond. 15,528 participants were included in the initial cohort, of which 2,331 completed all the questionnaires and did not have any missing data at the one-year follow-up. The mean age was 21, and four out of five were women. ADHD symptoms were assessed at the initiation of the study. Suicidal ideation was evaluated through a questionnaire completed a year later. Before that, three months after initiation, participants filled out a mental health survey that inquired about two potential mediators of suicidal ideation: depressive symptoms and self-esteem.

After adjusting for potential confounding factors (e.g., sex, childhood adversity, living conditions, and substance use) and taking into account the role of the mediators, the effect of ADHD symptoms on suicidal ideation (i.e., the direct effect) was no longer statistically significant, whereas pathways through depressive symptoms and self-esteem were both statistically significant. The pathway through depressive symptoms accounted for 25% of the total effect, while the pathway through self-esteem accounted for 64% of the total effect. Most of this indirect effect of self-esteem was in turn explained by the unique effect of self-esteem (not explained by depression), which accounted for 45% of the association, whereas a smaller part was explained by the effect of self-esteem through depression (accounting for 19% of the total effect). Ultimately, both mediators had the same effect (45% vs. 44%). Patterns were similar for males and females.

The authors caution that the study sample was not representative of the population of college students. It relied on volunteers, females were overrepresented, and the dropout ratio was very high. Participants in the final sample were more satisfied with their financial resources during their college years and during childhood, and less frequently consumed tobacco, than those in the initial cohort. The researchers recommend that ADHD patients be screened for self-esteem, and point out that other studies have indicated that exercise, Internet support groups, and interpersonal group therapy can build self-esteem in young people.

October 19, 2021
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ADHD in College Students - Selected by the APA as January’s ‘Member Course of the Month

ADHD in College Students - Selected by the APA as January’s ‘Member Course of the Month

ADHD continues to be a significant and difficult challenge in the collegiate world.

The symptoms of the disorder directly impact a person’s ability to manage the demands of college. Matriculating students are expected to rapidly obtain and deploy many self-management skills. Increased academic expectations demand a greater capacity for sustained attention. And the evolving social milieu can tax the emotion-regulation and social cognition of those with ADHD.

Having seen our patients struggle, the Association for Collegiate Psychiatry decided to submit a workshop for presentation at the 2019 APA meeting in San Francisco. While developing the presentation, we discovered a wealth of recent ‘young adult’ follow-up data from longitudinal studies.

Without exception, the study's findings reflected a significant decrease in functional outcomes across multiple domains of adult life. Further, we discovered that the new work coming from the TRAC observational study of college students has found troublesome rates of psychiatric comorbidity after the first year. This epidemiologic evidence supports devoting resources to the care of this cohort.

However, it appears that this has not penetrated the world of campus mental health treatment. At present, most post-secondary schools (to our knowledge, data is quite limited) lean toward policies that make it difficult for students with ADHD to be diagnosed or treated on campus. One obstacle is requiring evidence of a childhood diagnosis, which many children with high-IQ compensated ADHD may not have received. Another can be the demand for expensive and comprehensive neuropsychological testing even though the diagnostic value of that testing remains unclear.

Some student health centers ask students to obtain prescriptions from the treaters they saw before coming to campus, even if those prescribers are out of state. Though these policies may be deployed to decrease the diversion of stimulant medication, such hurdles may be difficult for the 18-year-old ADHD student to navigate. The result is that many students with this predictably destructive condition go untreated.

The good news is this subject interests the collegiate community. Among other things, our APA workshop was selected to be the APA’s ‘Member’s of the Month’ for January 2020. Much work remains in developing and deploying diagnostic policies and treatment strategies that colleges and universities feel comfortable supporting. We mentioned the APSARD community during the workshop as a resource for professionals interested in ADHD. And we hope the wider ADHD research and treatment communities will join us in focusing our energy on this underserved and sometimes maligned group of students who need our help.

September 10, 2021
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Comorbidities and Risk of Premature Death in Individuals With ADHD

How do psychiatric comorbidities affect risk of premature death among children and adults with ADHD?

Comorbidities contribute substantially to premature mortality risks in ADHD patients, but even those with ADHD alone are at a 40% greater risk.


The Nordic countries maintain detailed registers of their inhabitants. This enables researchers to examine patterns over entire nations. An international research team used the Swedish national registers for a prospective cohort study of 2,675,615 persons in the Medical Birth Register born in Sweden over 27 years from January 1, 1983, through December 31, 2009. Follow-up was completed in December 2013, with the oldest cohort member aged 31. The mean age at study entry was 6, and the mean at follow-up was 11.

Using personal identification numbers, researchers were able to cross-reference with the National Patient Register and the National Drug Register. From this, they determined that 86,670 members of the cohort (3.2 percent) had ADHD, based either on records of clinical diagnosis or of prescription of ADHD drugs. Psychiatric comorbidities were likewise identified in the National Patient Register.

These comorbidities were significantly more prevalent in the ADHD population than in the rest of the cohort. For example, whereas only 2.2% of the non-ADHD group was diagnosed with substance use disorder (SUD), 13.3% of the ADHD group also had SUD, a six-fold difference. For depression, it was a seven-fold difference; for schizophrenia a nine-fold difference.

The ADHD group had a significantly higher risk of premature death from all causes than the non-ADHD group, with an adjusted hazard ratio(HR) of 3.94 (95% CI 3.51-4.43). Unintentional injury (36%) and suicide (31%)were the leading causes of death in the ADHD group. Those with ADHD were more than eight times more likely to die by suicide than non-ADHD individuals and roughly four times more likely to die from unintentional injury.

The vast majority of the increased risk appears to be associated with comorbid psychiatric conditions. Those with ADHD but no diagnosed comorbidities had an adjusted HR of 1.41 (95% CI 1.01-1.97). With a single comorbidity, the HR more than doubled to 3.71 (95% CI 2.88-4.78). With four or more comorbidities, it rose to a staggering 25.22 (95% CI 19.6-32.46).

The comorbid condition with the greatest impact was SUD, which increased the risk eight-fold by comparison with those with only ADHD (HR= 8.01, 95% CI 6.16-10.41). Anxiety disorder, schizophrenia, and personality disorder increased the risk about fourfold. Bipolar disorder, depression, and eating disorders increased risk by roughly two and a half times.

The co-variate analysis helped tease out what portion of the risk was associated with ADHD alone versus comorbid conditions. Adjusting for the year of birth, sex, birth weight, maternal age at birth, parental educational level, and parental employment status, those with ADHD (including comorbid conditions)were 2.7 times more likely to prematurely die of natural causes than those without. Adjusting for comorbid psychiatric conditions completely eliminated the risk from ADHD alone (HR = 1.01, 95% CI.72-1.42).

Likewise, those with ADHD (including comorbid conditions)were six times as likely to die of unnatural causes. Adjusting for early-onset comorbid disorders (such as conduct disorders, autism spectrum disorder, and intellectual disability) only modestly reduced the HR to 5.3, but further adjusting for later-onset comorbid disorders(including substance use disorder, depressive disorder, bipolar disorder, anxiety disorder, schizophrenia, personality disorder, and eating disorders)reduced the HR to 1.57 (95% CI 1.35-1.83), and reduced it to insignificance in the case of suicide (HR = 1.13, 95% CI .88-1.45).

Summing up, the lion's share of the greater risk of premature death in persons with ADHD is attributable to psychiatric comorbidities. Nevertheless, those with ADHD alone still face a 40 percent greater risk than those without ADHD.

The study did not examine the effects of ADHD medication, which the authors state should be analyzed because of documented potential benefits on ADHD symptoms and comorbid disorders.

The authors concluded, Among adults, early-onset psychiatric comorbidity contributed substantially to the premature mortality risks due to natural causes. On the other hand, later-onset psychiatric comorbidity, especially SUD, explained a substantial part of the risk for unnatural deaths, including all the risk of suicide deaths and most of the deaths due to unintentional injuries. These results suggest that overall health conditions and risk of psychiatric comorbidity should be evaluated clinically to identify high-risk groups among individuals with ADHD.

September 8, 2021
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Exploring The Long-term Effects of Treating ADHD with Methylphenidate

Are there adverse effects to long-term treatment of ADHD with methylphenidate?

Although this review highlights the need for further research, it also upholds previous studies which support Methylphenidate as a safe and effective ADHD medication.


Methylphenidate (MPH) is one of the most widely-prescribed medications for children. Given that ADHD frequently persists over a large part of an individual’s lifespan, any side effects of medication initiated during childhood may well be compounded over time. With funding from the European Union, a recently released review of the evidence looked for possible adverse neurological and psychiatric outcomes.

From the outset, the international team recognized a challenge: “ADHD severity may be an important potential confounder, as it may be associated with both the need for long-term MPH therapy and high levels of underlying neuropsychiatric comorbidity.” Their searches found a highly heterogeneous evidence base, which made meta-analysis inadvisable. For example, only 25 of 39 group studies reported the presence or absence of comorbid psychiatric conditions; even among those, only one excluded participants with comorbidities. Moreover in only 24 of 67 studies was the type of MPH used (immediate or extended-release) specified. The team, therefore, focused on laying out an “evidence map” to help determine priorities for further research.

The team found the following breakdown for specific types of adverse events:

·  Low mood/depression. All three non-comparative studies found MPH safe. Two large cohort studies, one with over 2,300 participants, and the other with 142,000, favored MPH over the non-stimulant atomoxetine. But many other studies, including a randomized controlled trial (RCT), had unclear results. Conclusion: “the evidence base regarding mood outcomes from long-term MPH treatment is relatively strong, includes two well-powered comparative studies, and tends to favor MPH.”

·  Anxiety. Here again, all three non-comparative studies found MPH safe. But only two of seven comparative studies favored MPH, with the other five having unclear results. Conclusion: “while the evidence about anxiety as an outcome of long-term MPH treatment tends to favor MPH, the evidence base is relatively weak.”

·   Irritability/emotional reactivity. A large cohort study with over 2,300 participants favored MPH over atomoxetine. Conclusion: “the evidence base  is limited, although it includes one well-powered study that found in favor of MPH over atomoxetine.”

·  Suicidal behavior/ideation. There were no non-comparative studies, but all five comparative studies favored MPH. That included three large cohort studies, with a combined total of over a hundred thousand participants, that favored MPH over atomoxetine. Conclusion: “the evidence base  is relatively strong, and tends to favor MPH.”

·  Bipolar disorder. A very large cohort study, with well over a quarter-million participants, favored MPH over atomoxetine. A much smaller cohort study comparing MPH with atomoxetine, with less than a tenth the number of participants, pointed toward caution. Conclusion: “the evidence base  is limited and unclear, although it includes two well-powered studies.”

·  Psychosis/psychotic-like symptoms. By far the largest study, with over 145,000 participants, compared MPH with no treatment and pointed toward caution. A cohort study with over 2,300 participants favored MPH over atomoxetine. Conclusion: “These findings indicate that more research is needed into the relationship between ADHD and psychosis, and into whether MPH moderates that risk, as well as research into individual risk factors for MPH-related psychosis in young people with ADHD.”

· Substance use disorders. A cohort study with over 20,000 participants favored MPH over anti-depressants, anti-psychotics, and no medication. Other studies looking at dosages and durations of treatment, age at treatment initiation, or comparing with no treatment or “alternative” treatment, all favored MPH except a single study with unclear results. Conclusion: “the evidence base … is relatively strong, includes one well-powered study that compared MPH with antipsychotic and antidepressant treatment, and tends to favor MPH.”

·Tics and other dyskinesias. Of four non-comparative studies, three favored MPH, the other, with the smallest sample size, urged caution. In studies comparing with dexamphetamine, pemoline, Adderall, or no active treatment, three had unclear results and two pointed towards caution. Conclusion: “more research is needed regarding the safety and management of long-term MPH in those with comorbidities or tic disorder.”

·  Seizures or EEG abnormalities. With one exception, the studies had small sample sizes. The largest, with over 2,300 participants, compared MPH with atomoxetine, with inconclusive results. Two small studies found MPH safe, one had unclear results, and two others pointed towards caution. Conclusion: “While the evidence is limited and unclear, the studies do not indicate evidence for seizures as an AE of MPH treatment in children with no prior history  more research is needed into the safety of long-term MPH in children and young people at risk of seizures.”

·  Sleep Disorders. All three non-comparative studies found MPH safe, but the largest cohort study, with over 2,300 participants, clearly favored atomoxetine. Conclusion: “more research is needed into the relationship between ADHD, sleep, and long-term MPH treatment.”

· Other notable psychiatric outcomes. Two non-comparative studies, with 118 and 289 participants, found MPH safe. A cohort study with over 700 participants compared with atomoxetine, with inconclusive results. Conclusion: “there is limited evidence regarding long-term MPH treatment and other neuropsychiatric outcomes, and that further research may be needed into the relationship between long-term MPH treatment and aggression/hostility.”

Although this landmark review points to several gaps in the evidence base, it mainly supports prior conclusions of the US Food and Drug Administration) and other regulatory agencies (based on short-term randomized controlled trials) that MPH is safe for the treatment of ADHD in children and adults. Given that MPH has been used for ADHD for over fifty years and that the FDA monitors the emergence of rare adverse events, patients, parents, and prescribers can feel confident that the medication is safe when used as prescribed.

September 6, 2021
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Adult ADHD: Diagnoses Versus Undiagnosed

How do undiagnosed but symptomatic adults compare with those diagnosed with ADHD?

The study team began with a representative sample of 69,972U. S. adults aged 18 years or older who completed the 2012 and 2013 U.S. National Health and Wellness Survey. These adults were invited to complete the Validate Attitudes and Lifestyle Issues in Depression, ADHD, and Troubles with Eating(VALIDATE) study, which included 1) a customized questionnaire designed to collect data on sociodemographic and clinical characteristics and lifestyle, and2) several validated work productivity, daily functioning, self-esteem, and health-related quality of life (HRQoL) questionnaires. Of the 22,937 respondents, 444 had been previously diagnosed with ADHD, and 1,055 reported ADHD-like symptoms but had no previous clinical diagnosis.

There were no significant differences between the two groups in terms of age, education, income, health insurance, and most comorbid disorders. But those who had not been previously diagnosed were significantly more likely to be first-generation Americans (p<.001), nonwhite (p<.001), unemployed (p=.024), or suffer from depression, insomnia, or hypertension.

After matching the two groups for sociodemographic characteristics and comorbid conditions, covariate comparisons were made between 436 respondents diagnosed with ADHD and 867 previously undiagnosed respondents. Among respondents who were employed, diagnosed individuals registered a mean work productivity loss of 29% as opposed to 49% for the previously undiagnosed (p<.001). They also registered a 37% level of activity impairment versus a 53% level among the undiagnosed(p<.001). On the Sheehan Disability Scale, which ranges from 0 (no impairment) to 30 (highly impaired), the diagnosed group had a mean of 10, as opposed to a mean of 15 for the undiagnosed (p<.001). Diagnosed respondents also significantly outperformed undiagnosed ones on the Rosenberg Self-Esteem Scale (19 versus 15, on a scale of 0 to 30, p<.001), and on two quality-of-life scales (p<.001).

Applying a linear regression mixed model to the matched sets, the diagnosed still scored 16 points better than the undiagnosed on the WPA I: GH Productivity Loss scale (p<.001), 14 points better on the WPA I: GH Activity Impairment scale (p<.001), 4.5 points better on the Sheehan Disability Scale(p<.001), almost 4 points on the Rosenberg Self-Esteem Scale (p<.0001), with comparable gains on the two quality-of-life scales (p<.001 and p<.0001).

The authors concluded, This comparison revealed that individuals who had been diagnosed with ADHD were more likely to experience better functioning, HRQoL [health related quality-of-life], and self-esteem than those with symptomatic ADHD. This result appears to be robust, withstanding several levels of increasingly rigorous statistical adjustment. That points to substantial benefits from the treatment that follows a diagnosis of adult ADHD.

September 4, 2021
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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
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Trigeminal nerve stimulation may be an effective non-drug treatment for ADHD

Trigeminal nerve stimulation may be an effective non-drug treatment for ADHD

A University of California at Los Angeles (UCLA) team has just reported on the first-ever, double-blinded, sham-controlled study of trigeminal nerve stimulation (TNS) for treating ADHD. The trigeminal nerve is the largest cranial nerve. It enables facial sensation, as well as biting and chewing.

Over four weeks, researchers fitted 62 eight-to-twelve-year-old children with electrodes while they slept; 32 got an active low current, the rest none at all. The active and sham setups were identical in appearance. The children were told, pulses may come so fast or so slowly that the nerves in the forehead might or might not detect a sensation. After the four weeks, there was an additional-blinded week without intervention.

The primary efficacy outcome measure was the clinician-completed ADHD-RS total score, derived from parent interviews and available clinical information. It was completed at the onset of the study, and repeated over subsequent weeks. The Clinical Global Impression (CGI) score was used as a secondary outcome measure.

Both groups of children showed significant reductions in ADHD symptoms over the first week. But University of California at Los Angeles (UCLA) teams leveled off during the remaining three weeks for the group with sham treatment, while scores continued to decline for those in the group with actual stimulation. The standardized mean difference (SMD) between groups was 0.5.

By the conclusion of week 4, 52 percent of those in active treatment were improved or very much improved, as indicated by CGI scores; only a 14percent did as well with the sham treatment. The number needed to treat was just 3.

After discontinuation of treatment, total scores in both groups rose at similar rates. At the end of week 5, CGI ratings for active treatment showed 13 percent improvement over baseline, versus 7 percent for sham treatment. The SMD was 0.46, once again indicating the persistence of a medium effect size a week after treatment cessation.

The effect sizes computed for TNS are roughly comparable to effect sizes for non-stimulant medication, but less than those for stimulants.

Though the active group had significant gains in weight and pulse over the sham group, there were no serious adverse events in either group.

The authors concluded: Results from the Early Impressions Questionnaire showed no differences in outcome expectations between treatment groups after 1 week of using the randomized device, suggesting that our sham procedures successfully accomplished double-blinding of group assignment. Improvements seen in the active and sham groups at week 1 likely reflect some placebo response secondary to the high level of parental involvement in administering treatment. Nonetheless, a further improvement over subsequent weeks with active TNS suggests the emergence of true treatment effects TNS is a non-medication, minimal-risk intervention with proven efficacy in alleviating ADHD symptoms. Although the present study finds that only slightly more than half of those receiving therapy have clinically meaningful improvement, the virtual lack of significant side effects should make it a popular treatment choice for many patients with ADHD, particularly for parents who prefer to avoid psychotropic medication.

Nevertheless, one must keep in mind that this is a single uncomplicated study with a small sample size. Further, studies with larger numbers of participants are needed, both to confirm the efficacy and to further explore the weight gains and higher pulse rates in the treatment group.

August 31, 2021
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