It seemed like a routine test: collecting urine samples from 190 Spanish children to better understand ADHD. But what researchers at theUniversitat Rovira i Virgili surprised them too. Children with attention deficit hyperactivity disorder had significantly higher concentrations of lead, cadmium, copper and antimony in their urine. We are not talking about acute poisonings, but those everyday exposures that we consider normal. The discovery suggests that the causes of ADHD may be more environmental than we thought. And that changes everything for prevention.
The ADHD Test That Surprised Researchers
The study, published in Journal of Attention Disorders, he analyzed 190 children between 6 and 15 years old from Barcelona and Tarragona. Of these, 124 had a confirmed diagnosis of ADHD and 66 were healthy controls. The team of Sharanpreet Kaur e Josefa Canals-Sans tested 15 different metals in urine, looking for correlations with symptoms of the disorder.
The results were unequivocal. Children with the highest levels of lead in urine were 5 times more likely to have ADHD. For the Copper, the risk even increased 16-fold. Even cadmium e antimony showed significant associations with diagnosis.
But the most interesting thing emerged when the researchers analyzed the specific symptoms. Copper and cadmium were particularly linked to problems of carelessness (more common in girls), while copper and antimony correlated with hyperactivity and impulsivity.
Where are these metals hidden?
The sources of exposure are closer than we imagine. Lead comes from old pipes and paints, but also from contaminated urban soil and industrial dust. Cadmium is found in cereals, spinach, peanuts and fertilizers. Copper can come from pots, old pipes and drinking water. Antimony, on the other hand, hides in plastic bottles and industrial emissions.
Children from Tarragona showed higher levels of some substances due to specific regional factors, confirming that the local environment does play a role in the causes of ADHD.
ADHD, the puzzle of multiple causes
Attention (better to be clear): this study does not say that heavy metals they cause ADHD, but which could contribute to the risk. ADHD in fact has aheritability of 70-80%, but genes don't explain everything. The environment can influence gene expression through epigenetic mechanisms, creating a complex intertwining of nature and nurture.
Come I was underlining in this article, the brain develops in continuous interaction with the external environment. And if that environment contains neurotoxic substances, neurodevelopment can take different paths.
Moreover, this is not the first time that these connections have emerged. A 2024 meta-analysis of over 25.000 children confirmed that Lead exposure increases the risk of ADHD by 95%. The arsenic e Manganese show significant associations in some contexts.
Daily prevention strategies
The good news is that we can reduce exposure. Using water filters, avoiding hot tap water for cooking, maintaining a varied diet to limit cadmium accumulation, and practicing good hygiene to avoid accidental ingestion of contaminated dust are all practical steps.
Supplements of iron, zinc, calcium e omega-3, together with vitamins C and E, can help block the absorption of heavy metals and support cognitive function.
This research is not meant to scare, but to open up new possibilities. If the causes of ADHD include modifiable environmental factors, then prevention becomes more concrete. It is not about replacing existing therapies, but about adding an important piece to the puzzle of understanding and preventing this widespread disorder.
