Acetaminophen and Autism & ADHD Overview
Medicines containing acetaminophen are among the most widely used painkillers in the country. They are considered safe for consumers of all ages, from infancy to adulthood, including pregnant women and infants. An estimated 70% of women use acetaminophen while pregnant.
A growing body of research links prenatal (before birth) and postnatal (after birth) acetaminophen use to autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) later in childhood. According to one study which measured the amount of acetaminophen in newborn umbilical cord blood, children with the highest levels of acetaminophen in their cord blood were nearly three times more likely to be diagnosed with ADHD later in childhood and more than 3.5 times more likely to be diagnosed with ASD compared to children with lower levels of acetaminophen exposure.
Makers of acetaminophen-containing products ignored evidence of the increased risk for an ADHD and ASD diagnosis. They also failed to warn pregnant women about the risks acetaminophen posed to their unborn babies and young children.
If you have a child diagnosed with ADHD or autism who was exposed to acetaminophen before or shortly after birth, you may be entitled to compensation.
Acetaminophen and Autism & ADHD — What’s the Connection?
Acetaminophen is an aspirin-free pain reliever and fever reducer. The medicine is in over 600 products.
Acetaminophen use dramatically increased in the U.S. in the 1980s after the Centers for Disease Control and Prevention (CDC) recommended stopping prenatal and pediatric use of aspirin. Epidemiological evidence linked aspirin in children under 16 to Reye’s syndrome, a rare condition that can cause serious brain and liver damage.
One of the first studies to link acetaminophen to autism was published in the journal Autism in 2008 by Stephen T. Schultz and colleagues. Researchers surveyed parents of 83 children with autism and 80 without about whether their children were treated with acetaminophen or ibuprofen after receiving the measles-mumps-rubella (MMR) vaccination. Researchers found that ibuprofen use was not associated with an increased risk of autism, but acetaminophen was.
Schultz questioned whether the increase in autism diagnoses since the 1980s may be related to the CDC’s recommendations to replace prenatal and pediatric use of aspirin with acetaminophen.
Schultz also noted that the highly publicized product tampering cases of cyanide-laced acetaminophen, which led to significant decreases in sales of the medicine in 1982 and 1986, also coincided with plateaus in the incidence of autism in California.
The Mounting Evidence Linking Acetaminophen to Autism & ADHD
Since Schultz’s 2008 theories, more evidence has come out linking acetaminophen to ADHD and/or autism.
Prenatal Use of Acetaminophen Linked to ADHD
JAMA Pediatrics published a study in 2014 by University of California, Los Angeles, researchers using data from more than 64,000 children and mothers enrolled in the Danish National Birth Cohort to examine medication side effects on the children of pregnant women. They found those born to women who used acetaminophen while pregnant were 13% to 37% more likely to be diagnosed with hyperkinetic (hyperactive) disorder, treated with ADHD medications, or have ADHD-like behaviors by age 7. The risk was even greater among children whose mothers used acetaminophen for more than 20 weeks during pregnancy. Researchers noted that acetaminophen can cross the placental barrier, the tissues between maternal and fetal blood that exist to regulate the transfer of substances between the maternal and fetal circulation. They suggested that acetaminophen may interrupt fetal brain development by interfering with maternal hormones or through neurotoxicity.
Postnatal Use of Acetaminophen Linked to Autism
A 2017 study in the Journal of Internal Medical Research suggests that autism could be “an acetaminophen-induced brain injury.” They also conclude that the use of acetaminophen in babies and young children may be more strongly associated with autism than its use in pregnancy due to a body’s inability to process the medication in early development. The researchers called for “extreme urgency in probing the long-term effects of acetaminophen use in babies and the possibility that many cases of infantile autism may be induced by acetaminophen exposure shortly after birth.”
Cord Blood Links Acetaminophen to ADHD and Autism
Johns Hopkins Bloomberg School of Public Health researchers published a study in JAMA Psychology in 2019 that analyzed umbilical cord blood samples from the Boston Birth Cohort for acetaminophen. They found that children whose cord blood samples contained the highest levels of acetaminophen were nearly three times more likely to be diagnosed with ADHD and more than 3.5 times more likely to have autism than children with cord blood samples with the lowest levels of the medicine.
Large Studies Confirm Acetaminophen and ADHD, Autism Link
A study published in a 2018 edition of the American Journal of Epidemiology involved questionnaires from 132,738 pairs of mothers and children with follow-ups from 3 to 11 years. Researchers found that children born to women who used acetaminophen for an extended time while pregnant had a 20% greater risk of autism and a 30% greater risk of ADHD.
A University of Barcelona study published in May 2021 in the European Journal of Epidemiology involving more than 73,000 mother-and-child pairs across Europe found that children exposed to acetaminophen before birth were 19% more likely to have autism and 21% more likely to show signs of ADHD. “The most consistent pattern of results was observed for the association between prenatal acetaminophen exposure and ADHD symptoms,” the researchers wrote. They said the link was there in both boys and girls but was slightly stronger in boys.
Despite these findings, the manufacturers of acetaminophen-containing products continued to market acetaminophen to pregnant women—and pharmacies continued to sell it to them—without warning women of the risks acetaminophen posed to unborn and young children.
How Does Acetaminophen Cause Autism or ADHD?
Researchers are still trying to understand how acetaminophen can cause ADHD or autism. Some studies suggest the bodies of children with ASD do not process acetaminophen as well as children who do not have autism. Acetaminophen is considered safe at low doses. But high doses can cause acute liver failure in both adults and children. Experiments in laboratory mice have also shown that the painkiller is toxic to brain cells at lower concentrations than what is typically linked to acetaminophen-related liver damage. This suggests that children with ASD may be at greater risk of brain injury from significant acetaminophen exposure.
Autism vs. ADHD
Autism and ADHD are two different conditions, but they have many similarities. Both are neurodevelopmental disorders, meaning they each affect brain development. And both impact the central nervous system, which is responsible for movement, language, memory, and social and focusing skills. According to CHADD (Children and Adults with Attention-Deficit Hyperactivity Disorder), both are more common in boys, and the rates for both disorders are rising.
About 1 in 44 children in the U.S. is diagnosed with autism compared to 1 in 59 eight years ago and 1 in 125 in 2004, according to the CDC. In a 2015-2016 study, ADHD affected 10.2% of children ages 4 to 17, up from 9.0% eight years prior, according to CHADD.
While some ADHD and ASD symptoms may overlap, there are some distinct differences:
| Autism spectrum disorder | ADHD |
| Affects language skills, behavior, socializing, and the ability to learn | Affects concentration, ability to sit still, and impulsivity |
| Difficulty focusing on things they don’t like and may fixate on things they do like | Avoid things that require them to concentrate |
| Less social awareness of others, difficulty making eye contact and putting words to their thoughts | May talk constantly and/or interrupt when someone else is speaking. |
| Prefer order and repetition, doesn’t like change | Doesn’t like doing the same thing over again or for long periods |
Some children can be diagnosed with both conditions at the same time:
- ADHD is the most coexisting condition in children with ASD.
- Between 30% and 50% of children with ASD also have symptoms of ADHD.
- Up to 25% of children with ADHD have low-level signs of ASD, such as difficulty in social situations or sensitivity to clothing textures.
Acetaminophen and Autism & ADHD Lawsuits
On July 10, 2022, a group of plaintiffs filed a motion with the U.S. Judicial Panel on Multidistrict Litigation, seeking to consolidate acetaminophen autism lawsuits filed in the federal court system before one judge. The number of acetaminophen autism lawsuits filed in the U.S. is expected to climb as more people become aware of the dangers of acetaminophen in pregnant women and young children and Big Pharma’s failure to warn them of these risks.
Acetaminophen and Autism & ADHD Lawyers
Despite mounting evidence linking ADHD and autism to exposure to acetaminophen prenatal and shortly after birth, manufacturers of acetaminophen-containing products continued to market the medicine to pregnant women—and pharmacies continued to sell it to them—without warning parents of the risks acetaminophen posed to unborn babies and young children.
If you took acetaminophen while pregnant or treated your young child with acetaminophen for pain associated with vaccinations, and they were diagnosed with autism or ADHD, we can help. Contact us for a no-cost consultation.
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