Pain killer Paracetamol (Acetaminophen) use in pregnancy linked to ADHD

Acetaminophen, also known as Paracetamol in UK or Tylenol in US, a common pain reliever considered safe for pregnant women, has been linked for the first time to an increased risk of attention deficit and hyperactivity disorder in children, said a study, published Monday.

More studies are needed to confirm the findings, but experts said the research points to a new potential cause for the worldwide rise in cases of ADHD, a neuro-behavioural condition which has no known cause and affects as many as five percent of US children.

Women who took acetaminophen, also known as Paracetamol, while pregnant had a 37 percent higher risk of having a child who would be later given a hospital diagnosis of hyperkinetic disorder, a particularly severe form of ADHD, said the study in February 24 edition of the Journal of the American Medical Association (JAMA) Pediatrics: doi:10.1001/jamapediatrics.2013.4914.

Compared to women who did not take Acetaminophen while pregnant, women who did also had a 29 percent higher chance of having children who were later prescribed medications for attention deficit hyperactivity disorder, and a 13 percent higher chance of exhibiting ADHD-like behaviours by age seven.

Previous research has suggested that Acetaminophen can interfere with normal hormone function and may affect the developing fetal brain.

The painkiller has also been linked to a slightly increased risk in boys of cryptorchidism, a condition in which the testicles do not descend.

The latest research was based on survey data on more than 64,000 Danish women from 1996 to 2002.

More than half said they took Acetaminophen at least once during pregnancy.

Peer group experts cautioned that; 'The observational findings do not prove that taking Paracetamol or Tylenol-like pain relievers causes ADHD, only that a preliminary link between the two has appeared and would need to be confirmed by further research.'

Miriam Cooper

"Findings from this study should be interpreted cautiously and should not change practice," said an accompanying editorial in JAMA Pediatrics by Miriam Cooper and colleagues at the Cardiff University Institute of Psychological Medicine and Clinical Neurosciences.

"However, they underline the importance of not taking a drug's safety for granted, especially during pregnancy."

The reasons the women took the painkillers could have also had a confounding effect on the outcome, they added.

The study was led by Zeyan Liew, of the University of California, Los Angeles, and was co-authored by Jorn Olsen of the University of Aarhus in Denmark.

Racial and Ethnic disparities in ADHD diagnosis

Black children and children in homes where a language other than English is spoken are less likely to receive an attention-deficit/hyperactivity disorder (ADHD) diagnosis by school entry, despite being otherwise similar to white children on many measured background characteristics, according to a study by a team of researchers.

Their findings indicate that disparities in ADHD diagnosis begin to occur early in children's school careers.

Paul Morgan

"We were interested in evaluating whether the disparities observed across elementary and middle school in our earlier study were evident as early as the fall of kindergarten, accounting for many factors measured prior to the children entering school," said Paul Morgan, associate professor of special education, Penn State.

"Whether these disparities extend to Hispanic children has also been unclear. We find that their initially observed disparities are related to non-English language use in the home."

Analyses of kindergarten teacher-reported classroom behaviour indicated that neither black nor Hispanic children displayed less frequent ADHD-related behaviours than white children, suggesting that a lower incidence of ADHD symptomology did not explain minority children's comparatively lower rates of diagnosis.

"One explanation for our findings is that black parents may be relatively more reluctant to obtain a mental health diagnosis for their children, while language barriers may explain Hispanic children's lower likelihood of diagnosis," Morgan said.

"It may also be the case that pediatricians and other professionals are not soliciting developmental concerns as often from minority families."

A lack of treatment for ADHD may result in some minority children experiencing more learning and behavioral problems as they start school, so that they quickly begin falling behind their peers.

"One practical application is that these groups of children may have unmet treatment needs," Morgan said.

"Pediatricians, psychiatrists and school-based practitioners should be sensitive to the possibility that cultural and linguistic barriers are resulting in systematic under-diagnosis for some groups of children."

"Ensuring minority children are appropriately diagnosed and treated for ADHD may require overcoming these barriers."

Providing minority parents with information on recognizing potential ADHD symptoms in their children, as well as encouraging help-seeking behaviours when meeting with professionals, may also help prevent or reduce racial/ethnic diagnosis disparities.

"I hope that our findings inform efforts to help all children with ADHD," Morgan said. "If untreated, ADHD can very quickly begin to interfere with children's opportunities for school success."

More information: "Racial/ethnic disparities in ADHD diagnosis by kindergarten entry." Morgan PL, Hillemeier MM, Farkas G, Maczuga S. J Child Psychol Psychiatry. 2014 Jan 24. DOI: 10.1111/jcpp.12204. [Epub ahead of print]