May 19, 2021

OTHER MYTHS ABOUT ADHD

Myth: ADHD is an American disorder.
Those who claim ADHD is an American disorder believe that ADHD is due to the pressures of living in a fast-paced, competitive American society.   Some argue that if we lived in a simpler world, ADHD would not exist.  

Fact:  ADHD occurs throughout the world.

Wherever scientists have searched for ADHD, they have found it.  They have done this by going to different countries, and speaking to people in the community to diagnose them with or without ADHD.   These studies show that ADHD occurs throughout the world and that the percentage of people having ADHD does not differ between the United States and the rest of the world.   Examples of where ADHD has been found include  Australia, Brazil, Canada, China, Colombia, Finland, Germany, Iceland, Israel, Italy, Japan, New Zealand, Spain, Sweden, Taiwan, The Netherlands, and Ukraine.   ADHD is not an American disorder.

Myth: A child who sits still to watch TV or play video games cannot have ADHD.
Many parents are puzzled that their child can sit still to watch TV or play video games for hours, but that same child cannot sit still for dinner or stay at their desk for long to do homework.  Are these children faking ADHD symptoms to get out of homework?

Fact:  ADHD does not necessarily interfere with playing video games or watching TV.

Because children cannot turn their ADHD on and off to suit their needs, it does seem odd that a child who is typically hyperactive and inattentive can sit for hours playing a video game.  But this ability of ADHD children fits in very well with scientific facts about ADHD. First, you probably understand the effects of rewards and punishment on behavior.  If your behavior is rewarded, you are likely to do it again.  If it is punished, you will avoid that behavior in the future.  Rewards that have the strongest effect on our behavior are large and will occur soon. For example, consider these two choices:
a)      if you listen to a boring one-hour lecture, I will pay you $100 immediately after the lecture
b)      if you listen to a boring one-hour lecture, I will pay you $110 one year after the lecture
Choice (a) is more appealing than choice (b).  Most people will not think it is worthwhile to wait one year for $10.  We say they have 'discounted' the $10 to $0.
Now consider the choices:
c)      if you listen to a boring one-hour lecture, I will pay you $100 immediately after the lecture
d)     if you listen to a boring one-hour lecture, I will pay you $2,000 one year after the lecture

Choice (d) is more appealing than choice (c).  Most people will wait one year for$2,000.   It is obvious here is that if I want the best chance of having you watch a lecture, I should offer you a large sum of money immediately after the lecture. What is not so obvious is that people vary a great deal in the degree to which they are affected by rewards that are either small or distant in the future.   For some people, getting $2,000in one year is almost like getting nothing at all.  We say that such people are not sensitive to distant rewards.

What does this have to do with ADHD and video games?  Well, people with ADHD are usually not very sensitive to weak or distant rewards.  To affect the behavior of a person with ADHD, the reward needs to be immediate and fairly large.  When a child with ADHD sits down to do homework, the potential reward is getting a good grade on their report card, but they won't receive that grade for weeks or months, so it is very distant.  Thus, it is not surprising that the possibility of that reward cannot control the child's behavior.  In contrast, video games are created so that players are rewarded very frequently by winning points or completing one of the many levels one must pass to finally complete the game.  Because playing well is also rewarded by friends, the video game rewards are strong and immediate, which makes it easy for people with ADHD to sit still and play for long periods.

 Myth: ADHD disappears in adulthood.
Until the 1990s, it was commonly believed that children grew out of ADHD.  The reason for this is not clear.  Some theories about ADHD suggested that ADHD children had a lag in brain development, and that they would make up for that lag during adolescence.  So ADHD was seen as a delay in brain development that could be overcome.   The idea that children routinely recovered from ADHD was so strong that many insurance companies would not pay for the ADHD treatment of adults.

Fact: In the majority of cases, ADHD persists into adulthood.
This myth about ADHD has been proven wrong by studies that diagnosed ADHD in children and then examined it many years later than in adults.  These studies showed that, although there was some recovery from ADHD, about two-thirds of cases persisted into adulthood. The studies also taught us that ADHD symptoms tend to change with age.  The extreme and disruptive hyperactivity of many ADHD children gets somewhat better by adulthood, as do some symptoms of impulsivity.   In contrast, inattentive symptoms do not decrease much with age.

 Myth: People with ADHD cannot do well in school or succeed in life.
This myth is based on several facts: 1) ADHD affects many aspects of life; 2) ADHD impairs thinking and behavior and 3) for most people, ADHD is a lifelong disorder.   Altogether, doesn't this mean that people with ADHD won't succeed in life?

Fact: People with ADHD can succeed and live productive lives.
There are two reasons why people with ADHD can succeed in life. The first is obvious.  Although treatments for ADHD are not perfect, they can eliminate many of the obstacles that would otherwise make it difficult for ADHD patients to do well in school or on the job.  But, more importantly, having ADHD is only one of many facts about a person's life.   Some ADHD people have other skills or traits that help them compensate for their ADHD.  For example, if you have a high level of intelligence, an engaging personality, or excellent athletic skills, you can do well despite having ADHD.   Consider Michael Phelps, who broke so many Olympic swimming records. He was diagnosed with ADHD at age 9 and took Ritalin to help his hyperactivity.   James Carville has ADHD, but he completed law school and helped Bill Clinton become President of the United States.  Cammi Granato's ADHD did not stop her from becoming captain of the United  States Olympic ice hockey team, and Ty Pennington's ADHD did not stop him from becoming a  star on TV.

 Myth: ADHD does not affect highly intelligent people
The mistake behind this myth is that it assumes that being very intelligent protects people from having ADHD.  It's true that if you are highly intelligent, you can use that intelligence to compensate for some ADHD' effects, but does high intelligence completely protect a person from ADHD?

Fact: People with ADHD can succeed and live productive lives.
When my colleagues and I studied this question, we found clear evidence that high intelligence does not completely protect people from ADHD. Like people who don't have ADHD, having high intelligence will help Alderpeople do better than ADHD people who are not smart.  But when we compared highly intelligent Alderpeople with highly intelligent non-ADHD people, we found that the highly intelligent ADHD people had many of the impairing problems that are known to be associated with ADHD.  For details about these problems, see Complications of ADHD.  In another study, we compared ADHD adults who had received straight A grades in high school, with non-ADHD people who had achieved the same grades.  Despite their good grades, these ADHD adults were not doing as well in their jobs and not earning as much income as the non-ADHD adults.  And ADHD also has an impact at every level of education.  As you can see from the figure, even for people with college degrees, having ADHD lowers your chances of being employed.

Faraone, S. V., Sergeant, J.,Gillberg, C. &Biederman, J. (2003). The Worldwide Prevalence of ADHD: Is it an American condition? World Psychiatry2, 104-113.Polanczyk, G., de Lima, M. S., Horta, B. L., Biederman, J. &Rohde, L. A. (2007). The Worldwide Prevalence of ADHD: a systematic Review and Meta-regression Analysis. Am J Psychiatry164,942-8.
Scheres, A., Lee, A. &Sumiya,M. (2008). Temporal reward discounting and ADHD: task and symptom-specific effects. J Neurol Transm115, 221-6.
Faraone, S., Biederman, J. &Mick, E. (2006). the Dependent Decline Of Attention-Deficit/Hyperactivity Disorder:  Aneta-Analysis Of Follow-Up Studies. Psychological Medicine36,159-165.

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Updates on ADHD and Vitamin D

The Background on ADHD and Vitamin D

In a blog published in the early days of The ADHD Evidence Project, we discussed an Iranian study examining the association between Vitamin D levels and ADHD in children. The meta-analysis combined 13 studies for a total of 10,344 participants. The researchers found that youth with ADHD had "modest but significant" lower serum concentrations of 25-hydroxyvitamin D compared to those without ADHD.

They also identified four prospective studies that compared maternal vitamin D levels with the subsequent development of ADHD symptoms in their children. Two of these used maternal serum levels, and two used umbilical cord serum levels. Together, these studies found that low maternal vitamin D levels were associated with a 40% higher risk of ADHD in their children. 

Ultimately, the researchers noted that this result "should be considered with caution" because it was heavily dependent on one of the prospective studies included in the analysis. We concluded our blog by pointing out that further research, including more longitudinal studies, is needed before clinicians should start recommending vitamin D supplementation to ADHD patients. 

Further Research: 

Since publishing that initial blog, several more studies have been published about this association. 

The World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Disorders (CANMAT) convened an international task force involving 31 leading academics and clinicians from 15 countries between 2019 and 2021. Their goal was to provide a definitive, evidence-based report to assist clinicians in making decisions around the recommendation of nutraceuticals and phytoceuticals for major psychiatric disorders.

For ADHD, the guidelines found only weak support for micronutrients and vitamin D in treatment. Overall, the task force concluded that nutraceuticals and phytoceuticals currently offer very limited evidence‑based benefit for ADHD management.

Another study published in 2023 systematically assessed the results of previously published studies to examine the associations between maternal vitamin D levels, measured as circulating 25(OH)D levels in pregnancy or at birth, and later offspring psychiatric outcomes. This study found a clear association between maternal vitamin D deficiency and subsequent offspring ADHD. They concluded, “Future studies with larger sample sizes, longer follow-up periods, and prenatal vitamin D assessed at multiple time points are needed.”  To that, I will add that studies of this issue should use genetically informed designs to avoid confounding.

Conclusion:

Taking into account the updated research on the topic, there does seem to be an association between low prenatal vitamin D levels and the risk of subsequent offspring ADHD, but it is too soon to say it is a causal relationship due to the possibility of confounding. There is no high-quality evidence, however, that supplementing with vitamin D will significantly reduce symptoms in current ADHD patients. 

July 28, 2025

What Metabolites Tell Us About ADHD — And What This Means for Diet and Treatment

New research has uncovered important links between certain blood metabolites and ADHD by using a genetic method called Mendelian randomization. This approach leverages natural genetic differences to help identify which metabolites might actually cause changes in ADHD risk, offering stronger clues than traditional observational studies.

Key Metabolic Pathways Involved:

The study found 42 plasma metabolites with a causal relationship to ADHD. Most fall into two major groups:

  • Amino acid metabolites from protein metabolism, including those related to tyrosine, methionine, cysteine, and taurine.

  • Fatty acids, especially long-chain polyunsaturated fatty acids (PUFAs) like DHA and EPA, important for brain function.

What Does This Mean for Diet and ADHD?

Since many metabolites come from dietary sources like proteins and fats this supports the idea that diet could influence metabolic pathways involved in ADHD. However, because the study focused on genetic influences on metabolite levels, it doesn’t directly prove that dietary changes will have the same effects.

Notable Metabolites:

  • 3-Methoxytyramine sulfate (MTS): linked to dopamine metabolism, higher genetic levels of MTS were associated with a lower risk of ADHD. Dopamine plays a crucial role in attention and behavior.

  • DHA and EPA: Omega-3 fatty acids abundant in the brain; higher levels were linked to reduced ADHD risk, supporting existing research on omega-3 supplements.

  • N-acetylneuraminate: Involved in brain development and immune function, with higher levels linked to increased ADHD risk, though more research is needed to understand this.

Five metabolites showed bidirectional links with ADHD, meaning genetic risk for ADHD also affects their levels which suggests a complex interaction between brain function and metabolism.

Twelve ADHD-related metabolites are targets of existing drugs or supplements, including:

  • Acetylcysteine: an antioxidant used in various treatments.

  • DHA supplements: widely used to support brain and heart health.

What This Study Doesn’t Show

While these findings highlight biological pathways, they don’t prove that changing diet will directly alter ADHD symptoms. Metabolite levels are shaped by genetics plus environment, lifestyle, and health factors, which require further study.

Conclusion: 

This research provides stronger evidence of metabolic pathways involved in ADHD and points to new possibilities for diagnosis and treatment. Future work could explore how diet or drugs might safely adjust these metabolites to help manage ADHD.

While this study strengthens the link between amino acid and fatty acid metabolism and ADHD risk, suggesting that diet could play a role, ultimately more research is still needed before experts could use this research to give specific nutritional advice.

July 21, 2025

Network Meta-analysis Explores Long-term Efficacy of Nonpharmacological Treatments for Improving Inhibitory Control in Children and Adolescents with ADHD

Background Info:

Executive functions include inhibitory control, working memory, and cognitive flexibility. Inhibitory control is the ability to suppress distractions and focus on goals, which is the main deficit in ADHD. 

Children and adolescents with ADHD often have off-task, unrelated thoughts and are easily distracted, limiting their sustained attention. This makes it difficult for them to focus on tasks and leads to impulsive behaviors that affect their daily life, academics, and social interactions. Improving inhibitory control in ADHD children and adolescents is essential. 

Stimulant medications are commonly used to treat ADHD. However, side effects like insomnia, loss of appetite, and headaches may make parents hesitant to use these medications for their children. 

Non-pharmacological treatments like cognitive training, behavior therapy, and physical exercise have gained attention for their lack of side effects. Research shows that some non-pharmacological methods can improve cognitive outcomes significantly, underscoring their potential in treating ADHD. 

Study:

A Chinese research team identified four key gaps in current research on non-pharmacological treatments for inhibitory control in children with ADHD: 

  • Existing meta-analyses seldom differentiate between short-term and long-term interventions.  
  • Most studies focus primarily on short-term effects and neglect evaluation of maintenance effects through follow-up assessments.  
  • New treatment methods, such as meditation and board games, have not been systematically assessed in meta-analyses for their impact on inhibitory control in children and adolescents with ADHD, leaving their effectiveness uncertain.  
  • Traditional meta-analysis does not tell us which intervention is most effective. Without this comparative analysis, it is difficult to rank efficacy. 

The team therefore performed a network meta-analysis of long-term randomized controlled trials (RCTs) to assess and rank the effectiveness of various non-pharmacological treatments on inhibitory control in children and adolescents with ADHD. 

The team included only RCTs relying on professional diagnoses of ADHD, excluding those based only on parent and teacher rating scales.  

The included studies measured inhibitory control using objective neurocognitive tasks, such as the Stroop test and the Go/No-Go test, to reduce potential subjective bias. Studies relying on parent- or teacher-reported questionnaires were excluded. 

Controls either received no intervention or placebo, such as watching running videos and attending history classes. 

Meta-analysis of 16 studies combining 546 participants found large short-term effect size improvements in inhibitory control from physical exercise. But the two studies with a total of 110 participants that performed a follow-up test reported only a small-to-medium effect size improvement. 

For cognitive training, a meta-analysis of fifteen studies totaling 674 participants reported a medium effect size of short-term improvement in inhibitory control. The ten studies with 563 participants that performed a follow-up test found only a small effect size improvement since treatment initiation. 

For behavioral therapy, meta-analysis of six studies encompassing 244 individuals likewise found a medium effect size short-term improvement in inhibitory control. In this case, however two studies combining 91 participants that performed a follow-up test reported that the medium effect size improvement was maintained. 

For neurofeedback, meta-analysis of seven studies encompassing 186 individuals found a small-to-medium effect size short-term improvement in inhibitory control. The only study that performed a follow-up test reported a small effect size improvement since treatment initiation. 

The two studies with a combined 44 individuals exploring board games found no significant improvement in inhibitory control. Likewise, the two studies combining 32 participants that explored meditation found no significant improvement in inhibitory control. 

There was no indication of publication bias. 

Conclusion:

The team concluded, “Existing evidence shows that physical exercise, behavior therapy, cognitive training, and neurofeedback can effectively improve the inhibitory control of children and adolescents with ADHD. However, meditation, EMG feedback, and board games did not significantly affect inhibitory control. Physical exercise has the best effect among all non-pharmacological treatments, but its impact will be weakened after intervention. Behavior therapy and cognitive training had a slightly lower effect, but they have a better maintenance effect.” 

Ultimately, the study results suggest that non-drug treatments can help children and teens with ADHD improve their ability to control their actions and stay focused. Some methods, like physical exercise, work well at first but may fade once the activity stops. Other methods, like behavioral therapy and cognitive training, may take a little longer to show results but can last longer and make a bigger difference over time. Ultimately, and most importantly, because this work did not study the symptoms of ADHD or its real-world impairments, it provides no reason to change current treatment practices for ADHD.

July 16, 2025