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October 10, 2025
Vitamins play important roles in metabolism, immune regulation, and neurodevelopment. Recent studies show that deficiencies in vitamins like D, B6, B12, and folate are common in people with ADHD and ASD (autism spectrum disorder), and are associated with behavioral, cognitive, and brain development issues.
The Study:
A study team based in China has just performed a systematic search of the peer-reviewed medical literature to perform meta-analyses of clinical trials exploring vitamin interventions in the treatment of ADHD and ASD.
ADHD trials included participants with an official diagnosis. The primary intervention was vitamin supplements, while other treatments, including medications, remained unchanged or were excluded during the study period. ADHD outcomes included measurable changes in ADHD symptoms using validated rating scales and executive function measures.
Eligible studies included standard or sham control groups, crossover, parallel, or other clinical trial designs. In crossover studies, only first-phase data were analyzed to prevent carryover effects.
Ten trials with 852 participants met the standards, but meta-analysis showed no significant results. The outcomes varied widely, suggesting a need to distinguish among vitamins.
Results:
Of the five trials involving 347 participants that specifically evaluated vitamin D supplementation, results indicated a large effect size improvement in ADHD symptoms and executive function measures. The other five studies did not show any observable improvement.
Key limitations include:
The team concluded, “This meta-analysis supports the use of vitamin supplementation as a promising adjunctive treatment for ASD and ADHD. Vitamin B showed greater benefits in improving symptoms of ASD, while vitamin D was more effective in managing ADHD-related behaviors. These findings suggest that specific vitamins may target disorder-specific symptoms. Despite limitations such as the lack of trials on other vitamins and limited understanding of underlying mechanisms, vitamin therapy remains a low-cost, accessible option.”
An important limitation of this work is that the positive results for vitamin D were due to two studies from Iran. So far, no positive study has emerged from a non-Iranian study.
Interpretation:
The vitamin D findings are intriguing and could be important if replicated outside of Iran. Since supplementation is already widely recommended to those with limited sunlight exposure, clinicians may want to consider monitoring their patients’ vitamin D intake, especially in the winter months. It should be noted, however, that due to the limitations of this study, the results are by no means conclusive, and vitamin D should not be taken as a stand-alone treatment for ADHD.
Yonghui Shen, Yangbing Xie, Yadan Zheng, Yanbin Zheng, and Yan Liu, “Vitamin Interventions in ASD and ADHD: Systematic Review and Meta-Analysis,” Neuropsychiatric Disease and Treatment (2025) 21:1845-1855, https://doi.org/10.2147/NDT.S553063.
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.
A large international research team has just released a detailed analysis of studies looking at the connection between parents' mental health conditions and their children's mental health, particularly focusing on ADHD (Attention Deficit Hyperactivity Disorder). This analysis, called a meta-analysis, involved carefully examining previous studies on the subject. By September 2022, they had found 211 studies, involving more than 23 million people, that could be combined for their analysis.
Most of the studies focused on mental disorders other than ADHD. However, when they specifically looked at ADHD, they found five studies with over 6.7 million participants. These studies showed that children of parents with ADHD were more than eight times as likely to have ADHD compared to children whose parents did not have ADHD. The likelihood of this result happening by chance was extremely low, meaning the connection between parental ADHD and child ADHD is strong.
The researchers wanted to figure out how common ADHD is among children of parents both with and without ADHD. To do this, they first analyzed 65 studies with about 2.9 million participants, focusing on children whose parents did not have ADHD. They found that around 3% of these children had ADHD.
Next, they analyzed five studies with over 44,000 cases where the parents did have ADHD. In this group, they found that 32% of the children also had ADHD, meaning about one in three. This is a significant difference—children of parents with ADHD are about ten times more likely to have the condition than children whose parents who do not have ADHD.
The researchers also wanted to see if other mental health issues in parents, besides ADHD, were linked to ADHD in their children. They analyzed four studies involving 1.5 million participants and found that if a parent had any mental health disorder (like anxiety, depression, or substance use issues), the child’s chances of having ADHD increased by 80%. However, this is far less than the 840% increase seen in children whose parents specifically had ADHD. In other words, ADHD is much more likely to be passed down in families compared to other mental disorders.
The study had a lot of strengths, mainly due to the large number of participants involved, which helps make the findings more reliable. However, there were also some limitations:
Despite these limitations, the research team concluded that their analysis provides strong evidence that children of parents with ADHD or other serious mental health disorders are at a higher risk of developing mental disorders themselves. While more research is needed to fill in the gaps, the findings suggest that it would be wise to carefully monitor the mental health of children whose parents have these conditions to provide support and early intervention if needed
If we are to read what we believe on the Internet, dieting can cure many of the ills faced by humans. Much of what is written is true. Changes in dieting can be good for heart disease, diabetes, high blood pressure, and kidney stones to name just a few examples. But what about ADHD? Food elimination diets have been extensively studied for their ability to treat ADHD. They are based on the very reasonable idea that allergies or toxic reactions to foods can have effects on the brain and could lead to ADHD symptoms.
Although the idea is reasonable, it is not such an easy task to figure out what foods might cause allergic reactions that could lead to ADHD symptoms. Some proponents of elimination diets have proposed eliminating a single food, others include multiple foods, and some go as far as to allow only a few foods to be eaten to avoid all potential allergies. Most readers will wonder if such restrictive diets, even if they did work, are feasible. That is certainly a concern for very restrictive diets.
Perhaps the most well-known ADHD diet is the Feingold diet(named after its creator). This diet eliminates artificial food colorings and preservatives that have become so common in the western diet. Some have claimed that the increasing use of colorings and preservatives explains why the prevalence of ADHD is greater in Western countries and has been increasing over time. But those people have it wrong. The prevalence of ADHD is similar around the world and has not been increasing over time. That has been well documented but details must wait for another blog.
The Feingold and other elimination diets have been studied by meta-analysis. This means that someone analyzed several well-controlled trials published by other people. Passing the test of meta-analysis is the strongest test of any treatment effect. When this test is applied to the best studies available, there is evidence that the exclusion of fool colorings helps reduce ADHD symptoms. But more restrictive diets are not effective. So removing artificial food colors seems like a good idea that will help reduce ADHD symptoms. But although such diets ‘work’, they do network very well. On a scale of one to 10where 10 is the best effect, drug therapy scores 9 to 10 but eliminating food colorings scores only 3 or 4. Some patients or parents of patients might want this diet change first in the hopes that it will work well for them. That is a possibility, but if that is your choice, you should not delay the more effective drug treatments for too long in the likely event that eliminating food colorings is not sufficient. You can learn more about elimination diets from Nigg, J. T., and K.Holton (2014). "Restriction and elimination diets in ADHD treatment."Child Adolesc Psychiatr Clin N Am 23(4): 937-953.
Keep in mind that the treatment guidelines from professional organizations point to ADHD drugs as the first-line treatment for ADHD. The only exception is for preschool children where medication is only the first-line treatment for severe ADHD; the guidelines recommend that other preschoolers with ADHD be treated with non-pharmacologic treatments, when available. You can learn more about non-pharmacologic treatments for ADHD from a book I recently edited: Faraone, S. V. &Antshel, K. M. (2014). ADHD: Non-Pharmacologic Interventions. Child AdolescPsychiatr Clin N Am 23, xiii-xiv.
Boredom is more than just feeling restless or under-stimulated. It’s a negative emotional state that arises when activities feel meaningless or dull and, for those with ADHD, this negative emotional state might be markedly more intense. Researchers increasingly view boredom as functional: an internal signal pushing people to seek more rewarding and meaningful experiences. But for some, that signal becomes chronic and overwhelming.
People who are highly prone to boredom face a range of psychological and behavioral consequences, including anxiety, depression, difficulty identifying their own emotions (alexithymia), impulsivity, and physical complaints. These struggles often surface in harmful behaviors: overeating, substance use, compulsive internet use, and gambling.
For people with ADHD, boredom can cross into genuine distress. Many describe it as “torture” or “an itchy coat you can’t scratch”, language that conveys not mild discomfort but an urgent, almost unbearable need to escape. This makes sense given that ADHD involves core difficulties with attention, arousal regulation, and motivation, all of which make sustained engagement harder and boredom far more likely.
The Study:
A recent meta-analysis of 18 studies involving more than 22,000 participants confirmed a moderately strong and consistent positive association (an overall effect size of r = 0.40) between ADHD and self-reported boredom. All but one study found significant results, and there was no evidence of publication bias.
“While the relationship between ADHD and boredom may seem obvious,” the authors state, “this has paradoxically led to the phenomenon being understudied.”
Despite how significant this connection appears to be, the researchers noted it has attracted surprisingly little scientific attention; a gap they attribute to a widespread assumption that boredom in ADHD is simply a byproduct of inattention or impulsivity, and therefore not worth studying on its own terms. They push back on that view, arguing that boredom may be a more fundamental part of the ADHD experience: a bridge between atypical brain function and the behavioral, emotional, and cognitive difficulties that shape long-term outcomes.
The Take-Away:
Ultimately, addressing the profound boredom experienced by individuals with ADHD requires a multifaceted approach that goes beyond simply treating inattention. Researchers emphasize the need for rigorous studies to determine if stimulant medications actively reduce this intense boredom by repairing underlying brain mechanisms, rather than just as a side effect of improved focus. Beyond medication, tailored psychological therapies may offer promise; psychoeducation can help individuals reframe boredom as a biological signal rather than a personal failure or character flaw.
Additionally, another approach suggests that rather than solely focusing on treating the individual, systemic issues must be addressed, such as the effects of low-stimulation environments. For example, prioritizing a better "person-environment fit" through smaller class sizes, flexible academic pacing, and/or offering highly stimulating, novel tasks, schools and workplaces can offer meaningful relief from the chronic distress of ADHD-related boredom.
A new study from Japan suggests that infants born with craniosynostosis are significantly more likely to be diagnosed with ADHD later in childhood. Craniosynostosis is a condition in which the bony plates of the skull fuse prematurely, leading to increased intracranial pressure.
The Background:
Craniosynostosis affects roughly one in every 2,000 births. When the skull’s natural seams close prematurely, it can restrict brain growth and increase intracranial pressure, potentially reducing blood flow to the brain. Because the condition is relatively rare, it has been difficult to study at scale until now.
The Study:
To overcome this, researchers tapped into a large Japanese insurance database compiled by JMDC, Inc., which holds records on around 20 million people, or about 15% of Japan’s population. Drawing on two decades of data, the team tracked over 338,000 mother-child pairs. Children with related genetic syndromes or chromosomal conditions such as Down syndrome were excluded to keep the focus on craniosynostosis itself.
Of the children studied, around 1,145 had craniosynostosis, and 7,325 were diagnosed with ADHD. After accounting for factors like sex, birth year, maternal age, mental health history, pregnancy infections, and birth complications, children with craniosynostosis were found to have roughly 2.4 times the risk of a subsequent ADHD diagnosis compared to those without it.
To test whether shared family genetics or home environment might be driving the association rather than the skull condition itself, the researchers conducted a separate analysis among siblings. The elevated risk remained at 2.2 times. The consistency of the finding across both analyses strengthens the case for a genuine biological link.
The Results:
The results point to raised intracranial pressure and restricted cerebral blood flow as plausible mechanisms, though the study’s observational design means causation cannot be confirmed. Ultimately, these findings highlight the need for proactive, long-term care strategies for those born with craniosynostosis. By establishing a solid link between premature skull fusion and a significantly higher risk of ADHD, the research demonstrates that medical care for this condition should not end once the skull's physical structure is addressed.
The Takeaway:
Pediatricians, neurologists, and parents can use this data to implement early, routine behavioral and developmental screening for these children as they grow. This additional support would ensure that those who do develop ADHD can receive timely interventions, educational aids, and therapies, ultimately improving their long-term developmental outcomes.
Children and adolescents with ADHD come into contact with child welfare services (CWS) far more often than their peers. There are many contributing factors to consider, including the fact that hyperactivity and impulsivity frequently lead to behaviors that are considered disruptive and cause academic and social difficulties. Many of these children are also growing up in households marked by parental conflict and/or single-parent arrangements. All of these circumstances can compound vulnerability and, historically, increase the likelihood of CWS involvement.
Background:
In Norway, Child Welfare Services operate at the municipal level and are legally required in every local authority. Their scope spans investigation, family support, and, where necessary, out-of-home placement and ongoing monitoring. Grounds for intervention include abuse, neglect, behavioral or psychosocial difficulties, and inadequate care-giving. Norwegian CWS works closely with health, education, and social services and places a strong emphasis on keeping families together. Compared with systems in countries such as the United States, Poland, Romania, and the Czech Republic, the Norwegian approach sets a lower bar for intervention and leans toward home-based support, while setting a higher bar for out-of-home placements. This model is shared by other Nordic countries, as well as Germany and the United Kingdom.
Research into whether ADHD medication affects child welfare caseloads is remarkably sparse. A single Danish study previously found that medication treatment accounted for much of an observed decline in foster care cases, but no study had examined medication’s broader impact on CWS involvement, covering both supportive interventions and out-of-home placements.
Norway’s universal single-payer health system and comprehensive national registers make population-wide research of this kind feasible. Drawing on these resources, a Norwegian research team set out to test whether ADHD medication reduces children’s contact with CWS and their need for out-of-home placement.
The Study:
This study included all 5,930 children and adolescents aged 5 to 14 who received a clinical ADHD diagnosis from Child and Adolescent Mental Health Services between 2009 and 2011. Each was followed for up to 4 years post-diagnosis, the upper age limit being 18, at which point CWS jurisdiction ends. This group was compared with more than 53,000 peers who had no CWS contact during the same period.
The results showed a meaningful, though not dramatic, association between medication and reduced CWS contact. At one year, treated children had approximately 7% fewer contacts with CWS; by two years, that figure had risen to around 12%. The effect then narrowed, settling at roughly 7–8% reductions at the three- and four-year marks.
The picture for out-of-home placements is considerably less convincing. The research team highlighted a 3% reduction at two-year follow-up, but this finding barely crossed the threshold of statistical significance, and no effect was observed at the one-, three-, or four-year follow-up points.
The Take-Away:
The authors concluded that pharmacological treatment for ADHD is associated with reductions in both supportive CWS services and out-of-home placements among children affected by clinicians’ prescribing decisions in Norway. A more cautious reading of the same data, however, would emphasize an overall reduction in CWS contact of roughly 8%, while treating the out-of-home placement finding as, at best, inconclusive.
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