The median ferritin concentration in the children with ADHD was 7.71 micrograms per litre, with an interquartile range of 7.34 to 15.22, while the control group’s median stood at 30.52 micrograms per litre, spanning 23.38 to 37.66. That is roughly a fourfold gap between the two groups, and the difference was statistically significant at P less than 0.001. Zinc told a similar story. The ADHD group’s median serum zinc was 49.93 micrograms per decilitre, against 86.06 micrograms per decilitre in controls, again with a P value below 0.001. When the researchers applied conventional cutoffs, the picture became even more dramatic: 62.1 percent of the children with ADHD had ferritin below 15 micrograms per litre, a threshold often used to flag depleted iron stores, whereas not a single control child fell below that line. Using the reference interval supplied with the zinc assay kit, every one of the 66 children with ADHD had zinc below 70 micrograms per decilitre, compared with 14.5 percent of controls.

What makes these findings particularly noteworthy is that the children with ADHD were treatment-naive, meaning they had not yet received stimulant medication or other pharmacological therapy. This matters because some prior studies of nutrient status in ADHD have been confounded by the possibility that medication itself, or the appetite suppression it can cause, alters nutritional status. By measuring morning fasting blood samples before any treatment began, the Iraqi team reduced that concern, although it cannot be eliminated entirely in an observational design. All children in the ADHD group had parent and teacher Vanderbilt rating scales available, providing a standardized behavioral anchor for the diagnosis alongside the psychiatrist’s confirmation under DSM-5 criteria.

The statistical approach also deserves attention. Rather than running simple comparisons, the researchers used biomarker-specific Firth logistic regression, a method that performs well when outcome categories are unevenly distributed and when the goal is to estimate adjusted associations. After accounting for age and sex, higher concentrations of both ferritin and zinc remained associated with lower odds of being classified as having ADHD. In other words, the nutrient differences were not simply artifacts of the children with ADHD being younger or of a different sex distribution than the controls. The authors also reported a strong positive correlation between ferritin and zinc within the ADHD group itself, with a Spearman rank correlation coefficient of 0.861 and a P value below 0.001, suggesting that the two biomarkers tended to rise and fall together in these children.

Why would iron and zinc matter for a neurodevelopmental disorder? The biological rationale is grounded in decades of neuroscience. Iron is an essential cofactor for enzymes involved in the synthesis of dopamine, the neurotransmitter most closely implicated in ADHD pathophysiology, and it also supports myelination of neurons and the function of the basal ganglia circuits that regulate attention and motor control. Iron deficiency, even at subclinical levels, has been shown in animal models to alter dopaminergic signaling and to produce behavioral changes that resemble aspects of ADHD. Zinc, meanwhile, plays a role in neurotransmitter release and receptor function, including modulation of N-methyl-D-aspartate receptors, and it participates in the regulation of synaptic plasticity. Zinc deficiency has also been linked to disturbances in dopamine metabolism. The strong correlation between the two biomarkers in this study raises the possibility of a shared underlying cause, such as a common dietary pattern, but the researchers did not measure diet directly, so that interpretation remains speculative.

The authors are careful, and rightly so, to frame their results as evidence of association rather than causation. A case-control design like this one can show that two groups differ at a point in time, but it cannot establish whether low ferritin and zinc contribute to the development of ADHD, whether having ADHD somehow depletes these nutrients, or whether a third factor drives both. Children with ADHD may eat differently, sleep differently, or experience different levels of stress, any of which could influence nutritional biomarkers. The researchers also note that their subgroup findings remain exploratory, and they explicitly state that the study demonstrates no therapeutic benefit. That caveat is important because headlines about nutrient deficiencies in ADHD sometimes fuel unproven supplementation fads, and the study provides no evidence that giving iron or zinc to children with ADHD would improve their symptoms.

There are also clinical safety considerations that any discussion of supplementation must confront. Iron is not a benign substance; excess iron causes oxidative stress and organ damage, and indiscriminate supplementation in children who are not deficient can be harmful. Ferritin is also an acute-phase reactant, meaning it rises during inflammation, infection, or stress, so a single measurement can overestimate or underestimate true iron stores depending on the child’s health at the time. The study’s methodology acknowledged this challenge: the authors list C-reactive protein and erythrocyte sedimentation rate among their abbreviations, markers of inflammation that researchers in this field typically use to screen out children whose ferritin readings might be inflated by inflammatory processes. Zinc measurements, too, can be affected by recent meals, time of day, and hemolysis of the sample, which is why the fasting morning blood draws used in this study represent a methodological strength.

The Iraqi setting adds both value and context to the findings. Most of the existing literature on iron and zinc in ADHD comes from North America, Europe, Turkey, Iran, and East Asia, and the results across those studies have been heterogeneous, with some reporting significant differences and others finding none. Local data from Iraq have been limited, and nutritional deficiencies remain a public health concern in many parts of the region. The consistency and magnitude of the differences in this sample, particularly the complete absence of control children below the ferritin cutoff, suggests that iron depletion may be a genuinely common feature among children with ADHD in this population, or that the local dietary environment makes both groups vulnerable in ways that sharpen the contrast. Either way, the study provides a regional data point that global reviews of nutrition and ADHD have lacked.

The study’s design was ambispective, combining retrospective inclusion of eligible clinical and laboratory data collected before the study’s ethics approval with prospective recruitment and assessment afterward. It was conducted from January 2025 to April 2026 in Al-Najaf City and received approval from the Scientific Research Ethics Committee of the College of Medicine at the University of Kufa, with verbal informed consent obtained from parents or legal guardians for the prospective component. The research received no specific external funding, and the authors declared no competing interests. The sample size, while modest, is respectable for a single-center case-control study, and the use of validated behavioral rating scales from both parents and teachers strengthens the diagnostic assessment.

Where does this leave the field? The findings add weight to the hypothesis that peripheral iron stores and zinc status are linked to ADHD, at least in some populations, and they justify further research with longitudinal designs that follow children over time, measure dietary intake directly, and test whether correcting deficiencies changes clinical outcomes. Randomized controlled trials of supplementation in children with documented deficiency, rather than in unselected groups of children with ADHD, would be the logical next step, and such trials would need to monitor iron status carefully for safety. Until then, the practical takeaway for clinicians is nuanced: the study supports checking ferritin and zinc in children being evaluated for ADHD, particularly where deficiency is plausible, but it does not support empirical supplementation as a treatment for the disorder itself. The association is real and, in this Iraqi sample, remarkably strong; the therapeutic implications remain, for now, an open question that only intervention studies can answer.

Subject of Research: Serum ferritin and zinc concentrations in children with attention-deficit/hyperactivity disorder in Iraq

Article Title: Serum ferritin and zinc levels in Iraqi children with attention deficit hyperactivity disorder

Article References: Hashim, A. A., & Balasim, M. S. (2026). Serum ferritin and zinc levels in Iraqi children with attention deficit hyperactivity disorder. Discover Mental Health. https://doi.org/10.1007/s44192-026-00609-y

Image Credits: AI Generated

DOI: 10.1007/s44192-026-00609-y

Keywords: ADHD, ferritin, zinc, iron deficiency, children, Iraq, case-control study, neurodevelopmental disorders, dopamine, micronutrients, pediatrics, Discover Mental Health