What Causes ADHD?

Are Everyday Toxins Causing ADHD?

With diagnoses of attention deficit, autism, and learning disabilities on the rise, experts wonder whether toxins, inside and outside the home, could be causing ADHD in children and adults.

Triangular street sign with exclamation point in it and sky above symobolizing the potential toxic risk factors and their effects on ADHD diagnosis
Triangular street sign with exclamation point in it and sky above symobolizing the potential toxic risk factors and their effects on ADHD diagnosis

Do Chemicals Really Cause ADHD?

The number of reported cases of ADHD increased by 43 percent between 2003 and 2011, according to the CDC. Approximately 15 percent of U.S. children have a developmental disability, and research shows that the numbers are growing. Reported cases of autism spectrum disorders have gone up 119 percent since 2000. While increased awareness of symptoms and improved diagnostic criteria play a role in these statistics, studies controlling for those factors imply that other culprits — chemicals and gene-environment interactions — are contributing to the rising incidence.

Scientific research suggests that exposure to toxic chemicals — everyday toxins found in foods, carpeting and flooring, cleaning and lawn products, and personal-care products, like toothpastes — may contribute substantially to disorders such as ADHD, autism, and learning disabilities. Infants and children are especially vulnerable to toxic chemical exposure because their biological systems are still developing. During fetal development, exposure to even minuscule amounts of toxins at critical junctures can have a lifelong impact on the child’s brain and physical health. When toxins disrupt brain development, disabilities like ADHD can occur.

In 2010, the Learning and Developmental Disabilities Initiative (LDDI) released the first-ever report identifying toxic chemical pollution in people from the learning and developmental disability community, called “Mind, Disrupted: How Toxic Chemicals May Affect How We Think and Who We Are.” I was one of the participants.

How Toxins Alter Brain Development

Before I tell you about the chemical cocktail they found in my body, I want to explain how everyday toxins interfere with normal brain development. The most critical part of development takes place in the first trimester of pregnancy — when the cell architecture and connections between neurons are established. It is a complex process, directed by genes and chemicals called neuro-endocrines. Thyroid hormones, which are produced in precise amounts and at certain times, according to an individual’s genetic code, play a critical role in the process. It is for these reasons that some individuals with ADHD have a family or genetic history of the disorder. Many of those without a family history, though, show the same brain dysfunction due to toxins that disrupt the neuro-endocrine system.

According to the Endocrine Society, “numerous neurotransmitter systems, such as dopamine, norepinephrine, serotonin, glutamate, and others, are sensitive to endocrine disruption. Exposure to even small doses of endocrine disruptors can wreak subtle or serious havoc with the human endocrine system, which is highly sensitive.” Says Theo Colborn, Ph.D., coauthor of Our Stolen Future (#CommissionsEarned), “The endocrine system is so fine-tuned that it depends on changes in hormones in concentrations of a tenth of a trillion of a gram to control the womb environment. That’s as inconspicuous as one second in 3,619 centuries.”

Which Toxins Could Be Lurking In ADHD Bodies?

A year ago, I agreed to participate in that national study, conducted by the Learning and Developmental Disabilities Initiative, which tracked levels of environmental toxins in “normal” individuals. Blood and urine samples were taken to look for the presence of specific synthetic chemicals and heavy metals. Prior to receiving the results, I thought that those who lived near a toxic waste dump or in housing with lead-based paint were the only ones affected by toxins. I was wrong.

You don’t have to live next to a toxic waste site to be exposed to brain-damaging chemicals. For example:

  • Perfluorinated compounds (PFCs) are used to prevent food and other substances from sticking to carpets, drapes, and cooking pans. Teflon and Scotchgard are examples.
  • Polybrominated diphenyl ethers (PBDEs), used as fire retardants, are found in clothing and furniture, as well as bedding.
  • Triclosan is an antibacterial agent found in soaps, toothpastes, and many other personal-care products.
  • Bisphenol A (BPA) is an epoxy resin used to line food cans and other containers. It is also used to make plastic containers, like baby bottles, and certain paper products.
  • Phthalates make rubber-based materials soft and pliable. They are found in vinyl, plastic bottles, toys, shower curtains, and raincoats. They are also used to make personal-care products, air fresheners, and shampoos.

The Learning and Developmental Disabilities Initiative tested for 89 toxins, and it found 61 in several of the participants. Everyone, including me, tested positive for at least 26 of the chemicals. I had above-acceptable levels of PBDEs (found in flame retardants) and triclosan (in soaps and other personal-care products). I was high in organic pesticides, thanks to the chemicals sprayed on my lawn, and in PFCs — chemicals that discourage eggs from sticking to my frying pan.

Further evidence come from a 2015 study, completed by the University of Calgary, that linked the chemicals used in making plastic (BPA and BPS) to hyperactivity in zebrafish, which are often used to study embryonic brain development because they share 80 percent of the genes found in humans, and have similar developmental processes. They called the results of their study, “a smoking gun” that linked negative changes in brain development to BPA and BPS exposure.

Of course, lead exposure may also cause ADHD, according to a study published in Psychological Science in 2015. The study’s researchers emphasized that lead exposure is not the only cause of ADHD symptoms; rather, it’s one environmental factor that may lead to a formal ADHD diagnosis. Similarly, lead exposure doesn’t guarantee an ADHD diagnosis, but it may provide doctors with further clues about the root of a child’s symptoms.

How to Reduce Your Exposure to Dangerous Chemicals and Toxins

Alarmed at how many chemicals I tested positive for, I decided to work at decreasing my exposure to them. I could fire my lawn-care company and live with the weeds. I could buy organic food, and I could use chemical-free toothpastes. It quickly became apparent that these changes would require cost and effort.

Where does this leave you? You may think that it’s too late. You or one of your children has already been diagnosed with ADHD. Still, you can keep yourself informed and join with others who are fighting to change federal laws that regulate the companies making the chemicals. Visit the Healthy Children Project, part of the Learning Disabilities Association of America; Collaborative on Health and the Environment, which partners with the LDDI; and Institute for Children’s Environmental Health. Working to create a healthier environment will help more children reach their full potential.

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