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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.
The first few weeks of life are the time when babies are most vulnerable to seizures (known as neonatal seizures). This is partly because of events that can occur during birth, and partly because the newborn brain is naturally in a more excitable state than a mature brain, making it more prone to seizure activity.
Seizures affect roughly 1 to 3 in every 1,000 full-term babies born, and the rate is considerably higher in premature babies, at around 11 to 14 per 1,000. In most cases, seizures at this age are triggered by a specific event or injury affecting the brain. In full-term newborns, the most common cause is a condition called hypoxic-ischemic encephalopathy (HIE), which occurs when the brain is deprived of adequate oxygen and blood flow around the time of birth. Other causes include genetic or metabolic conditions, stroke, bleeding in the brain, and structural abnormalities in how the brain developed. In very premature babies, bleeding into the fluid-filled spaces of the brain (known as intraventricular hemorrhage) is the leading culprit.
Diagnosing seizures in newborns is tricky because many normal or abnormal movements and behaviors in this age group can look like seizures without actually being them. For this reason, monitoring the baby’s brain activity using an electroencephalogram (EEG) – a test that records electrical signals in the brain – is essential to confirm whether a seizure is truly occurring.
Sweden’s single-payer health system provides universal coverage, with national registers linking healthcare and population data. Researchers tracked infants with EEG/aEEG-confirmed seizures born between 2009 and 2020 and compared them to controls without neonatal seizures.
Altogether, 1062 infants with neonatal seizures were matched with 5310 controls.
The team adjusted for birth, mode of delivery, sex, birth weight, and Apgar scores – quick, standardized assessments used to evaluate newborns’ health minutes after birth.
With these adjustments, infants who had neonatal seizures were twice as likely to subsequently be diagnosed with ADHD and three times as likely to be subsequently diagnosed with autism spectrum disorder.
The authors emphasized that because the study was observational, it cannot demonstrate a direct cause-and-effect relationship between neonatal seizures and outcomes. Factors like seizure frequency, genetics, and socioeconomic status are thought to significantly impact the prognosis of affected children, but these could not be included in this study due to data limitations.
Background:
There are currently few long-term treatment options for adult ADHD. Psychostimulants can help reduce symptoms, but their benefits rely on availability, continued use, and are not easily tolerated by some. Cognitive-behavioral therapies have also proven to be helpful, but access is limited because they must be provided by trained specialists. These challenges highlight the need to explore alternative interventions that could provide cognitive and behavioral improvements with fewer side effects.
Exercise has shown potential as a nonclinical intervention for ADHD. Previous research indicates that physical activity can increase cortical volume, enhance brain activation, and boost connectivity in cognitive regions, as well as raise dopamine and norepinephrine levels – effects similar to psychostimulants. Research in children and teens with ADHD has found that both regular exercise programs and even single workout sessions can improve executive functions (mental skills like planning and self-control) and reduce core ADHD symptoms. But whether exercise helps adults with ADHD has remained an open question.
Study:
A Chinese sports medicine research team set out to answer this by reviewing all available peer-reviewed studies on exercise and adult ADHD. They found so few studies on regular exercise programs – only four total, and three of those were small pilot studies just testing whether the approach was feasible – that they couldn’t draw firm conclusions about long-term exercise interventions.
However, they were able to analyze four moderate-to-high-quality studies involving 152 adults with ADHD that tested single exercise sessions. The combined results showed moderate improvements in inhibitory control (the ability to resist impulses and stay focused). Adults not taking medication showed large improvements.
When they looked at four studies involving 170 adults, they found small but consistent improvements in core ADHD symptoms after single exercise sessions. There was little to no variation (heterogeneity) in individual study outcomes, and no sign of publication bias.
Results:
The team concluded, “Overall, these findings offer preliminary evidence on the potential role of exercise as a helpful strategy in the management of adult ADHD,” but cautioned that more well-designed randomized controlled trials are needed to determine the efficacy of both acute and chronic exercise interventions for adult ADHD, with particular emphasis placed on determining the best “prescription” for exercise – what type, how intense, and how often.
They also noted that most existing research has focused narrowly on attention and impulse control, while other important mental abilities like working memory and mental flexibility remain largely unexplored.
Take-Away:
The takeaway here is practical and accessible: you don't need a long-term fitness program to get a cognitive bump from exercise if you have ADHD. Even a single session appears to help — particularly with impulse control. While the research base is still thin and we don't yet know the ideal exercise "prescription," the risk-benefit calculation is hard to argue with. For adults with ADHD who can't access medication or therapy, or who simply want an additional tool, breaking a sweat may be worth building into the routine.
Background:
Non-suicidal self-injury (NSSI) means intentionally hurting yourself without trying to end your life. Common examples include cutting, scratching, or burning yourself. This behavior is most common in teenagers, affecting 13-20% of adolescents. It’s also called self-harm or deliberate self-injury.
Young people who struggle with managing emotions, act impulsively, or have mental health conditions like depression are more likely to self-harm.
Because ADHD involves impulsivity and often occurs alongside emotional difficulties, researchers have suspected a link between ADHD and self-injury. However, previous studies have tended to be small, unrepresentative, and inconsistent, making it hard to draw clear conclusions.
The Study:
Researchers combined results from 14 different studies involving nearly 30,000 people to get a clearer picture. They looked at children, teenagers, and adults with ADHD from various settings—including hospitals, community programs, and general population studies.
To be included, studies had to confirm ADHD diagnosis through professional evaluation or validated testing methods.
Key findings
Conclusion:
The researchers concluded that roughly one in four people with ADHD have engaged in non-suicidal self-harm. The findings suggest that ADHD and self-harm share overlapping vulnerabilities.
Overall, this meta-analysis strengthens evidence that people with ADHD face a significantly elevated risk of non-suicidal self-injury, likely reflecting overlapping challenges with impulsivity, emotional regulation, and co-occurring mental health conditions. Importantly, this does not mean self-harm is inevitable in ADHD. It does, however, highlight the need for early screening, supportive environments, and targeted mental-health care to help reduce risk and support healthier coping strategies.
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