The effect of adding ferrous sulfate to methylphenidate on attention-deficit/hyperactivity disorder in children

Iron Deficiency and Sleep/Wake Behaviors: A Scoping Review of Clinical Practice Guidelines-How to Overcome the Current Conundrum?

Current evidence suggests that iron deficiency (ID) plays a key role in the pathogenesis of conditions presenting with restlessness such as attention deficit hyperactivity disorder (ADHD) and restless legs syndrome (RLS). In clinical practice, ID and iron supplementation are not routinely considered in the diagnostic work-up and/or as a treatment option in such conditions. Therefore, we conducted a scoping literature review of ID guidelines. Of the 58 guidelines included, only 9 included RLS, and 3 included ADHD. Ferritin was the most frequently cited biomarker, though cutoff values varied between guidelines and depending on additional factors such as age, sex, and comorbidities. Recommendations surrounding measurable iron biomarkers and cutoff values varied between guidelines; moreover, despite capturing the role of inflammation as a concept, most guidelines often did not include recommendations for how to assess this. This lack of harmonization on the interpretation of iron and inflammation biomarkers raises questions about the applicability of current guidelines in clinical practice. Further, the majority of ID guidelines in this review did not include the ID-associated disorders, ADHD and RLS. As ID can be associated with altered movement patterns, a novel consensus is needed for investigating and interpreting iron status in the context of different clinical phenotypes.

Brain iron concentration in childhood ADHD: A systematic review of neuroimaging studies

Iron deficiency may play a role in the pathophysiology of Attention Deficit/Hyperactivity Disorder (ADHD). Due to its preponderant function in monoamine catecholamine and myelin synthesis, brain iron concentration may be of primary interest in the investigation of iron dysregulation in ADHD. This study reviewed current evidence of brain iron abnormalities in children and adolescents with ADHD using magnetic resonance imaging methods, such as relaxometry and quantitative susceptibility mapping, to assess brain iron estimates. The study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search was performed for studies published between January 1, 2008 and July 7, 2023 in Medline, Scopus and Proquest. Regions of interest, brain iron index values and phenotypical information were extracted from the relevant studies. Risk of bias was assessed using a modified version of the National Heart, Lung, and Blood Institute quality assessment tool. Seven cross-sectional studies comparing brain iron estimates in children with ADHD with neurotypical children were included. Significantly reduced brain iron content in medication-naïve children with ADHD was a consistent finding. Two studies found psychostimulant use may increase and normalize brain iron concentration in children with ADHD. The findings were consistent across the studies despite differing methodologies and may lay the early foundation for the recognition of a potential biomarker in ADHD, although longitudinal prospective neuroimaging studies using larger sample sizes are required. Lastly, the effects of iron supplementation on brain iron concentration in children with ADHD need to be elucidated.

Iron Supplementation in Management of Neurodevelopmental Disorders: Systematic Review, Meta-Analysis, and Qualitative Synthesis

OBJECTIVE

The authors sought to explore the role of iron supplementation in the management of neurodevelopmental disorders among children and youths.

METHODS

A systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was undertaken. A subset of results was suitable for meta-analysis. The quality of the evidence and strength of the clinical recommendations were assessed by using the Grading of Recommendations, Assessment, Development, and Evaluation method, and critical appraisal was conducted with the Joanna Briggs Institute critical appraisal tools.

RESULTS

Nine articles met inclusion criteria. These articles included studies of attention-deficit hyperactivity disorder (ADHD) (N=7), autism spectrum disorder (N=1), and Tourette's syndrome (N=1). Three randomized controlled trials evaluating iron supplementation for ADHD hyperactivity symptom severity (124 participants: placebo, N=56; supplement, N=68) met inclusion criteria for a meta-analysis. Effect sizes for the placebo and supplement groups were moderate (Cohen's d=0.76) and large (Cohen's d=1.70), respectively, although these differences were not significant. The impact of iron supplementation on inattentive ADHD symptom severity was examined in two trials (75 participants: placebo, N=31; supplement, N=44). Large, nonsignificant effect sizes were demonstrated for the placebo (Cohen's d=1.66) and supplementation (Cohen's d=3.19) groups. The quality of the evidence and strength of the clinical recommendations were considered very low.

CONCLUSIONS

Further research is needed to examine the role of iron supplementation in the management of ADHD and neurodevelopmental disorders more generally. Additionally, iron supplementation comes with risks, including death in the case of overdose.

Eating Patterns and Dietary Interventions in ADHD: A Narrative Review

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neurodevelopmental disorders in childhood, affecting ~7% of children and adolescents. Given its adverse health outcomes and high healthcare and societal costs, other treatment options beyond pharmacotherapy have been explored. Case-control studies have shown that dietary patterns may influence the risk of ADHD, and specific dietary interventions have been proposed as coadjuvant treatments in this disorder. These include nutritional supplements, gut microbiome-targeted interventions with biotics, and elimination diets. The purpose of this review is to examine which dietary patterns are most associated with ADHD and to summarize the existing evidence for the clinical use of dietary interventions. The literature showed that non-healthy dietary patterns were positively associated with ADHD, whereas healthy patterns were negatively associated. As for nutritional supplements, only vitamin D and vitamin D + magnesium appeared to improve ADHD symptoms when baseline levels of vitamin D were insufficient/deficient. Regarding biotics, evidence was only found for Lactobacillus rhamnosus GG and for multi-species probiotic supplementation. Elimination diets have scarce evidence and lead to nutritional deficiencies, so caution is advised. Overall, more robust scientific evidence is required for these dietary interventions to be implemented as part of ADHD therapy.

Iron deficiency and common neurodevelopmental disorders—A scoping review

Background

A wealth of human and experimental studies document a causal and aggravating role of iron deficiency in neurodevelopmental disorders. While pre-, peri-, and early postnatal iron deficiency sets the stage for the risk of developing neurodevelopmental disorders, iron deficiency acquired at later ages aggravates pre-existing neurodevelopmental disorders. Yet, the association of iron deficiency and neurodevelopmental disorders in childhood and adolescence has not yet been explored comprehensively.

In this scoping review, we investigate 1) the association of iron deficiency in children and adolescents with the most frequent neurodevelopmental disorders, ADHD, ASD, and FASD, and 2) whether iron supplementation improves outcomes in these disorders.

Method

Scoping review of studies published between 1994 and 2021 using “iron deficiency / iron deficiency anemia” AND “ADHD” OR “autism” OR “FASD” in four biomedical databases. The main inclusion criterion was that articles needed to have quantitative determination of iron status at any postnatal age with primary iron markers such as serum ferritin being reported in association with ADHD, ASD, or FASD.

Results

For ADHD, 22/30 studies and 4/4 systematic reviews showed an association of ADHD occurrence or severity with iron deficiency; 6/6 treatment studies including 2 randomized controlled trials demonstrated positive effects of iron supplementation. For ASD, 3/6 studies showed an association with iron deficiency, while 3/6 and 1/1 systematic literature review did not; 4 studies showed a variety of prevalence rates of iron deficiency in ASD populations; 1 randomized controlled trial found no positive effect of iron supplementation on behavioural symptoms of ASD. For FASD, 2/2 studies showed an association of iron deficiency with growth retardation in infants and children with prenatal alcohol exposure.

Conclusion

Evidence in favor of screening for iron deficiency and using iron supplementation for pediatric neurodevelopmental disorders comes primarily from ADHD studies and needs to be further investigated for ASD and FASD. Further analysis of study methodologies employed and populations investigated is needed to compare studies against each other and further substantiate the evidence created.

Withdrawing methylphenidate in relation to serum levels of ferritin and zinc in children and adolescents with attention-deficit/hyperactivity disorder

Iron and zinc have been associated with attention-deficit/hyperactivity disorder (ADHD), executive functioning, and response to methylphenidate, given their link with the dopaminergic system. This study aimed to investigate the effect of withdrawing methylphenidate after long-term treatment on serum levels of ferritin and zinc; and if baseline (pre-discontinuation) serum levels of these nutritional markers moderated the effects of withdrawing methylphenidate on ADHD and oppositional defiant disorder (ODD) symptoms, and working memory. Blood samples were collected from 63 children and adolescents who participated in a randomized, placebo-controlled methylphenidate discontinuation study. They were assigned to either seven weeks of continued treatment with methylphenidate or to gradual withdrawal to placebo. With mixed models for repeated measures we (i) compared changes in ferritin and zinc serum levels between both groups, and (ii) investigated moderating effects of ferritin and zinc on the effects of discontinuation on ADHD and ODD symptoms, and working memory. We additionally explored correlations of baseline and change serum levels with respective symptom scores. Withdrawing methylphenidate led to a decrease in ferritin levels. Higher baseline ferritin was associated with a larger increase (i.e., worsening) of teacher-rated hyperactivity-impulsivity and ODD symptoms after withdrawal; and higher baseline zinc with a larger increase in number of errors on the working memory task after withdrawal. Serum levels did not correlate with ADHD and ODD symptoms. Our preliminary results suggest that ferritin and zinc may be potential biomarkers for the effectiveness of long-term treatment with methylphenidate.

Effects of Iron Supplementation on Attention Deficit Hyperactivity Disorder in Children Treated with Methylphenidate

Objective

To evaluate the effect of iron on the attention deficit hyperactivity disorder, treated with methylphenidate.

Methods

This double-blind, randomized placebo-controlled clinical trial was performed on 50 children with attention deficit hyperactivity disorder under the treatment of methylphenidate, with ferritin levels below 30 ng/ml and absence of anemia. They were randomly assigned into two groups of ferrous sulfate and placebo, for 12 weeks. Conners' Parent Rating Scale (CPRS) was used to assess the outcome in the first, sixth, and twelfth weeks.

Results

Almost all CPRS subscales improved in the ferrous sulfate group from the baseline to the endpoint, although only the changes in conduct subscale scores were significant (p = 0.003). There was no significant difference in score changes between two groups in intergroup comparison. Also, the score of learning problems (p = 0.007) in the first six weeks, and conduct (p = 0.023) and psychosomatic (p = 0.018) subscales in the second six weeks were improved in the ferrous sulfate group compared with the placebo group.

Conclusion

Our study showed promising effects of iron supplementation in the improvement of subscales of the CPRS.

The Role of Iron and Zinc in the Treatment of ADHD among Children and Adolescents: A Systematic Review of Randomized Clinical Trials

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder common from childhood to adulthood, affecting 5% to 12% among the general population in developed countries. Potential etiological factors have been identified, including genetic causes, environmental elements and epigenetic components. Nutrition is currently considered an influencing factor, and several studies have explored the contribution of restriction and dietary supplements in ADHD treatments. Iron is an essential cofactor required for a number of functions, such as transport of oxygen, immune function, cellular respiration, neurotransmitter metabolism (dopamine production), and DNA synthesis. Zinc is also an essential trace element, required for cellular functions related to the metabolism of neurotransmitters, melatonin, and prostaglandins. Epidemiological studies have found that iron and zinc deficiencies are common nutritional deficits worldwide, with important roles on neurologic functions (poor memory, inattentiveness, and impulsiveness), finicky appetite, and mood changes (sadness and irritability). Altered levels of iron and zinc have been related with the aggravation and progression of ADHD. Objective: This is a systematic review focused on the contribution of iron and zinc in the progression of ADHD among children and adolescents, and how therapies including these elements are tolerated along with its effectiveness (according to PRISMA guidelines). Method: The scientific literature was screened for randomized controlled trials published between January 2000 to July 2021. The databases consulted were Medline, PsycINFO, Web of Science, and Google Scholar. Two independent reviewers screened studies, extracted data, and assessed quality and risk of bias (CONSORT, NICE, and Cochrane checklists used). Conclusion: Nine studies met the eligibility criteria and were selected. Evidence was obtained regarding the contribution of iron-zinc supplementation in the treatment of ADHD among young individuals. The discussion was focused on how the deficits of these elements contribute to affectation on multiple ADHD correlates, and potential mechanisms explaining the mediational pathways. Evidence also suggested that treating ADHD with diet interventions might be particularly useful for specific subgroups of children and adolescents, but further investigations of the effects of these diet interventions are needed.