March 12, 2021

Everything You Need to Know About ADHD

You've heard all sorts of misinformation about Attention-Deficit/Hyperactivity Disorder(ADHD), whether from friends, the internet, or uninformed press articles:

"ADHD is not real."

"Pharmaceutical companies invented ADHD to make money."

"I'm just a little ADD."

"Natural solutions are the best for ADHD treatment."

ADHD symptoms were first described in the late 1700s, primarily among hyperactive boys. It was described variously over 200 years as "fidgeting," "defects of moral control," "hyperkinetic reaction," "minimal brain damage" and eventually ADD (Attention Deficit Disorder) in the 1980s and ADHD today.

Because the natural tendency toward hyperactivity decreased with age, ADHD was originally thought to be a developmental disorder that disappeared in mid-to-late adolescence. When medicines were developed and used in ADHD treatment for young boys, physicians stopped prescribing them around mid-adolescence, because it was presumed the condition had been remediated. They were wrong. We know now that ADHD persists into adulthood for about two-thirds of ADHD youth.

ADHD was not widely recognized in girls until the mid-1990s when it became clear that girls with ADHD were less disruptive than boys with ADHD and were not being appropriately diagnosed. Girls with ADHD show less of the physical hyperactivity of boys, but suffer from "dreaminess," "lack of focus" and "lack of follow-through."

It was also in the 1990s that ADHD' pervasive comorbidity with depression, anxiety, mood, and autism spectrum disorders was established. At the same time, researchers were beginning to describe deficits in executive functioning and emotional dysregulation that became targets of substantial research in the 21st century.

Even with the 1990s recognition that ADHD is a lifetime disorder, equally present (in different forms) in both men and women, medical schools and continuing medical education courses (required for realizing sure of health professionals) have only begun to teach the most up-to-date evidence-based knowledge to the medical community. There still is much misinformation and a lack of knowledge among primary care professionals and the public.

ADHD Throughout the Lifespan
Most cases of ADHD start in Otero before the child is born. As a fetus, the future ADHD person carries versions of genes that increase the risk for the disorder. At the same time, they are exposed to toxic environments. These genetic and environmental risks change the developing brain, setting the foundation for the future emergence of ADHD.

In preschool, early signs of ADHD are seen in emotional lability, hyperactivity, disinhibited behavior and speech, and language and coordination problems. The full-blown ADHD syndrome typically occurs in early childhood, but can be delayed until adolescence. In some cases, the future ADHD person is temporarily protected from the emergence of ADHD due to factors such as high intelligence or especially supportive family and/or school environments. But, as the challenges of life increase, this social, emotional, and intellectual scaffolding is no longer sufficient to control the emergence of disabling ADHD symptoms.

Throughout childhood and adolescence, the emergence and persistence of the disorder are regulated by additional environmental risk factors such as family chaos, as well as the age-dependent expression of risk genes that exert different effects at different stages of development. During adolescence, most cases of ADHD persist and by the teenage years, many youths with ADHD have onset with a mood, anxiety, or substance use disorder. Indeed, parents and clinicians need to monitor ADHD youth for early signs of these disorders. Prompt treatment can prevent years of distress and disability.

By adulthood, the number of comorbid conditions increases, including obesity, which likely impacts future medical outcomes. Emerging data shows people with ADHD to be at increased risk for hypertension and diabetes. ADHD adults tend to be very inattentive but show fewer symptoms of hyperactivity and impulsivity. They remain at risk for substance abuse, low self-esteem, injuries due to accidents, occupational failure, and social disability, especially if they are not treated for the disorder.

Seven Important Concepts About ADHD


There are approximately 10 million U.S. adults with ADHD, 9 million of whom are undiagnosed. But with diligent research by the medical profession, we have learned seven important concepts about ADHD:
1.    ADHD has been documented worldwide in 5% of the population.
2.    Sixty-seven percent of ADHD children grow into ADHD adults and seniors. ADHD is heritable, runs in families, and is impacted by the physical environment and familial lifestyle.
3.    In youth, rates of ADHD are higher in males than females as males, but these rates even out by adulthood.
4.    ADHD coexists and is often masked by several other disorders: anxiety, depression, spectrum bipolar and autism disorder, substance abuse, alcoholism, obesity, risky behaviors, disorganized lives, working memory deficits, and significant executive dysfunctions that affect personal, social, and work success.
5.    ADHD medications(stimulants and non-stimulants) are the most effective treatments for ADHD symptoms. Psychological support/training designed for ADHD, and lifestyle modifications, are important adjuncts to medicine.
6.    ADHD costs the U.S. economy more than $100 million annually in lost productivity, accidents, hospitalizations with comorbidities, and family and professional support for ADHD patients.
7.    ADHD is diagnosable and safely treatable in trained primary care practices.

How do you know if you or someone you love has ADHD? Evaluate your life against the seven concepts above. Then get screened and diagnosed by a health care professional. The diagnosis of ADHD should be done only by a licensed clinician who has been trained in ADHD. That clinician should have one goal in mind: to plan a safe and effective course of evidence-based treatment.

When diagnosing adults, it is also useful to collect information from a significant other, which can be a parent for young adults or a spouse for older adults. But when such individuals are not available, diagnosing ADHD based on the patient's self-report is valid. Just remember that personal, work, and family lives are improved with treatment. Research and technology related to ADHD improve all the time.

ADHD in Adults is a great resource for anyone interested in learning more about ADHD, with evidence-based information and education for both healthcare professionals and the public. The website also features a new ADHD screener for predicting the presence of ADHD in adults.

Stephen V. Faraone, Ph.D., is a Distinguished Professor of Psychiatry and Neuroscience & Physiology at SUNY Update Medical University and a global expert on Adult ADHD.

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South Korean Nationwide Population Study: Prenatal Exposure to Acid-suppressive Medications Not Linked to Subsequent ADHD

Acid-suppressive medications, including proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists, are often prescribed during pregnancy to treat heartburn and gastroesophageal reflux disease. 

Research shows changes in the gut microbiome can negatively affect neurodevelopment. Since acid-suppressive medications alter gut microbiota, maternal use during pregnancy may impact offspring’s neurodevelopment. Because PPIs and H2 receptor antagonists readily cross the placental barrier, they could potentially influence fetal neurodevelopment.  

The link between prenatal exposure to acid-suppressive medications and major neuropsychiatric disorders is not well understood. With the use of these medications during pregnancy rising, it is important to assess their impact on children's long-term neurodevelopment. This study examined whether maternal use of acid-suppressive drugs is associated with increased risk of neuropsychiatric disorders in children, using a large, nationwide birth cohort from South Korea. 

South Korea operates a single-payer health insurance system, providing coverage for over 97% of its citizens. The National Health Insurance Service (NHIS) maintains a comprehensive database with sociodemographic details, medical diagnoses, procedures, prescriptions, health examinations, and vital statistics for all insured individuals. 

A Korean research team analyzed data from over three million mother-child pairs (2010–2017) to assess the risks of prenatal exposure to acid-suppressing medications. They applied propensity scoring to adjust for maternal age, number of children, medical history, and outpatient visits before pregnancy, to minimize confounding factors. That narrowed the cohort to just over 800,000 pairs, with half in the exposed group. 

With these adjustments, prenatal exposure to acid-suppressing medications was associated with 14% greater likelihood of being subsequently diagnosed with ADHD. 

Yet, when 151,737 exposed births were compared to the same number of sibling controls, no association was found between prenatal exposure and subsequent ADHD, which suggests unaccounted familial and genetic factors influenced the preceding results. 

The Take-Away:

Evidence of these medications negatively affecting pregnancies is mixed, mostly observational, and generally reassuring when these medications are used appropriately. Untreated GERD and gastritis, however, have known risks and associations with the development of various cancers. With no evidence of an association with ADHD (or for that matter any other neuropsychiatric disorder), there is no current evidence-based reason for expectant mothers to discontinue use of acid-suppressing medications.  

February 6, 2026

The 'Medication Tolerance' Myth in ADHD: What the Evidence Actually Says

For years, a persistent concern has shadowed the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD): Does the medication eventually stop working? Patients often report that their symptoms seem to return despite consistent use, leading to "dose escalation" or "medication holidays." A new systematic review from Sam Cortese’s team  published in CNS Drugs finally puts these concerns to the test by synthesizing decades of empirical research.

Before diving into the findings, you must understand two often-confused phenomena:

  • Tachyphylaxis (Acute Tolerance): A rapid decrease in response to a drug, often occurring within a single day (24 hours).
  • Tolerance: A gradual reduction in responsiveness over long-term exposure, requiring higher doses to achieve the original effect.

The review analyzed 17 studies covering over 10,000 individuals, and the results provide a much-needed reality check for the clinical community.

The researchers found preliminary evidence that acute tolerance (tachyphylaxis) can occur within a 24-hour window.

  • Subjective Effects: Studies showed that "drug liking" or feelings of euphoria from stimulants often peak and fade faster than the actual drug concentration in the blood.
  • Clinical Impact: This phenomenon is why some older, flat-release formulations were less effective than modern "ascending" delivery systems (like OROS-methylphenidate), which are designed to overcome this daily dip in efficacy.

The most important finding is that tolerance does not commonly develop to the therapeutic effects of ADHD medication in the long term. In one landmark study following children for up to 10 years, only 2.7% of participants lost their response to methylphenidate without a clear external explanation.  Doses, when adjusted for natural body growth, remained remarkably stable over years of treatment.

Consistent with the lack of therapeutic tolerance, the body does not become tolerant to the physical side effects of stimulants.  Increases in heart rate and blood pressure typically persist for as long as the medication is taken.  This underscores why clinicians must continue monitoring cardiovascular health throughout the entire duration of treatment.

If it’s Not Tolerance, What Is It?

If "tolerance" isn't real, why do some patients feel their medication is failing? The review suggests clinicians look at these alternative explanations:

  1. Natural Symptom Fluctuations: ADHD is not a static condition; symptoms naturally wax and wane over time regardless of treatment.
  2. Limited Compliance: Missed doses or inconsistent timing are often the real culprits behind "failing" efficacy.
  3. Life Events & Transitions: New jobs, academic pressures, or stressful life changes can increase the "functional demand" on a patient, making their current dose feel insufficient.
  4. Co-occurring Conditions: The emergence of anxiety, depression, or substance use disorders can mask or mimic a return of ADHD symptoms.

Why This Matters

These results provide clinicians the confidence to tell patients that their medication is unlikely to "wear out" permanently. Rather than immediately increasing a dose when symptoms flare, the first step should be a "clinical deep dive" into the patient's lifestyle, stress levels, and adherence.

For researchers, the review highlights a major gap: most existing studies are small, dated, or of low quality. There is a dire need for robust, longitudinal studies that track both the brain's response and the patient's environment over several years.

For people with ADHD, while your body might get "used to" the initial "buzz" of a stimulant within hours, its ability to help you focus and manage your life remains remarkably durable over the years.

Population Study Finds Association Between Extended Methylphenidate Use By Children and Subsequent Obesity

South Korean Nationwide Population Study Finds Association Between Extended Methylphenidate Use By Children and Subsequent Obesity–Little to No Effect on Adult Height

South Korean Nationwide Population Study Finds Association Between Extended Methylphenidate Use By Children and Subsequent Obesity–Little to No Effect on Adult Height

The Background:

Concerns remain about how ADHD and methylphenidate (MPH) use might affect children's health and growth, and especially how it may affect their adult height. While some studies suggest disrupted growth and a possible biological mechanism, the impact of ADHD prevalence and MPH use is still unclear. Children with ADHD may develop unhealthy habits – irregular eating, low physical activity, and poor sleep – that can contribute to obesity and reduced height. MPH’s appetite-suppressing effect can lead to skipped meals or overeating. Since growth hormone is mainly released during deep sleep, chronic sleep deprivation could plausibly slow growth and impair height development; however, a clear link between ADHD, MPH use, overweight, and shorter stature has never been firmly established. 

The Study:

South Korea has a single payer health insurance system that covers more than 97% of its population. A Korean research team used the National Health Insurance Service database to perform a nationwide population study to explore this topic further. 

The study involved 34,850 children, of whom 12,866 were diagnosed with ADHD. Of these children, 6,816 (53%) had received methylphenidate treatment, while 6,050 (47%) had not. Each patient with ADHD was precisely matched 1:1 by age, sex, and income level to a control participant without ADHD. The sex ratio was comparable in all groups.The team used Body Mass Index (BMI) as an indicator of overweight and obesity. 

The Results: 

The researchers found that being diagnosed with ADHD was associated with 50% greater odds of being overweight or obese as young adults, and over 70% greater odds of severe obesity (BMI > 30) compared to matched non-ADHD controls, regardless of whether or not they were medicated.

Those diagnosed with ADHD, but not on methylphenidate, had 40% greater odds of being overweight or obese, and over 55% greater odds of becoming severely obese, relative to matched non-ADHD controls. 

Methylphenidate users had 60% greater odds of being overweight or obese, and over 85% greater odds of becoming severely obese, relative to matched non-ADHD controls. 

There were signs of a dose-response effect. Less than a year’s exposure to methylphenidate was associated with roughly 75% greater odds of becoming severely obese, whereas exposure over a year or more raised the odds 2.3-fold, relative to matched non-ADHD controls. Using MPH increased the prevalence of overweight from 43.2% to 46.5%, with a greater prevalence among those using MPH for more than one year (50.5%).

It is important to note that most of this effect was from ADHD itself, with methylphenidate only assuming a predominant role in severe obesity among those with longer-term exposure to the medicine. 

As for height, children with ADHD were no more likely to be short of stature than matched non-ADHD controls. Being prescribed methylphenidate was associated with slightly greater odds (7%) of being short of stature, but there was no dose-response relationship. 

Conclusion: 

The team concluded, “patients with ADHD, particularly those treated with MPH, had a higher BMI and shorter height at adulthood than individuals without ADHD. Although the observed height difference was clinically small in both sexes and age groups, the findings suggest that long-term MPH exposure may be associated with growth and body composition, highlighting the need for regular monitoring of growth.” They also point out that “Despite these findings, the clinical relevance should be interpreted with caution. In our cohort, the mean difference in height was less than 1 cm (eg, maximum −0.6 cm in females) below commonly accepted thresholds for clinical significance.”  Likewise, increases in overweight/BMI were small. 

One problem with interpreting the BMI/obesity results is that some of the genetic variants that cause ADHD also cause obesity.  If that genetic load increases with severity of ADHD than the results from this study are confounded because those with more severe ADHD are more likely to be treated than those with less severe ADHD.

Due to these small effects along with the many study limitations noted by the authors, these results should be considered alongside the well-established benefits of methylphenidate treatment.

February 2, 2026