Scientists at Cardiff University say a new study has uncovered a direct genetic link between children diagnosed with ADHD, which they hope will reduce the stigma associated with the disorder.
Researchers found that rare copy number variants – where small segments of DNA are duplicated or missing – were twice as common in children with ADHD than those without the condition. (Copy number variants is abbreviated CNV.)
The study’s lead investigator, Professor Anita Thapar, explains in the video below the important new research behind the headlines. Congratulations and gratitude go to the hardworking scientists who teased out this discovery.
News Reporting Report Card
As for the news reporting of this research, some did better than others. Some claimed this is the first news of a genetic link to ADHD (nope). But at least it was cited as potential evidence that ADHD isn’t caused by bad parenting.
What? You say you already knew of the genetic link to ADHD? Of course you did.
It seems these news outlets missed a key adjective in Dr. Thapar’s explanation of her team’s research findings: direct. As in “the first direct genetic link to ADHD.”
Yet, even that is being contested; stay tuned for more info on that.
Here are excerpts from several outlets reporting on the findings.
For the first time, evidence has emerged of genetic mutations linked to attention-deficit hyperactivity disorder. But how strong is the genetic link to ADHD, and how far does the finding undermine claims that children with the condition are simply naughty kids, victims of bad parenting or driven to hyperactivity by dietary additives?
[The report includes that question.]
But the researchers found the CNVs in only 16 percent of the ADHD kids. Might bad parenting or poor diet have caused the disorder in all the rest?
Possibly. But the researchers say that when diet has been fingered as a culprit in ADHD and changed in an attempt to treat the condition, little good has come of it. And many children with ADHD have stable relationships with parents and are well behaved generally – their condition manifests itself only through an inability to concentrate and focus on specific tasks.
“There’s not a great deal of evidence for what the environmental factors might be,” said Thapar’s colleague Kate Langley. …
HealthDay/ Bloomberg BusinessWeek:
Gene Disorder Linked to ADHD [link no longer works]
Finding bolsters idea that condition has biological basis
WEDNESDAY, Sept. 29 (HealthDay News) — Many who suffer from attention-deficit hyperactivity disorder (ADHD) appear to have a genetic abnormality that may predispose them to the condition, British researchers report.
Their finding bolsters the belief that ADHD is not solely a social problem but can have origins in an individual’s biology. ADHD affects 3 percent to 5 percent of children in the United States, according to the U.S. National Institute of Mental Health.
“ADHD is a complex disorder, and we have known for quite some time that it has a strong genetic composition,” said lead researcher Nigel Williams, a senior lecturer in the department of psychological medicine and neurology at the Cardiff University School of Medicine in England.
“This is directly supported by our results, which provide direct evidence that ADHD is a neurodevelopmental disorder,” he said. …
Compelling new research released Thursday shows that attention deficit hyperactivity disorder — ADHD — may have genetic underpinnings. Reporting in the British medical journal The Lancet, scientists at Cardiff University in Wales found that people with certain genetic makeups may be more likely to have the disorder.
(Reuters) – British scientists have found the first direct evidence attention deficit/hyperactivity disorder (ADHD) is a genetic disorder. They say their research could eventually lead to better treatments for the condition.
Researchers who scanned the gene maps of more than 1,400 children found that those with ADHD were more likely than others to have small chunks of their DNA duplicated or missing.
Anita Thapar, a professor psychiatry at Cardiff University who led the study, said the findings should help dispel the myths that ADHD is caused by bad parenting or high-sugar diets.
“This is really exciting because it gives us the first direct genetic link to ADHD. Now we can say with confidence that ADHD is a genetic disease. And, the brains of children with this condition develop differently to those of other children,” she told reporters at a briefing about the findings.
The first direct evidence of a genetic link to attention-deficit hyperactivity disorder has been found, a study says.
Scientists from Cardiff University, writing in The Lancet, said the disorder was a brain problem like autism – not due to bad parenting.
[Preface to next paragraph: I can’t tell if the BBC editors were having a bit of fun by trotting out this character or if they really thought he would provide “balance” to the story; check out the second video at the BBC link above-Gina]
Oliver James, a clinical child psychologist and broadcaster, cited studies which looked at the effect of anxiety among pregnant women, and disturbed early relations between mothers and their babies. He said: “Only 57 out of the 366 children with ADHD had the genetic variant supposed to be a cause of the illness. That would suggest that other factors are the main cause in the vast majority of cases.
“Genes hardly explain at all why some kids have ADHD and not others.”
Somehow, I suspect James has no clue about genes. Speaking of no clue…..
Andrea Bilbow, OBE, ADDISS Executive Director
Andrea Bilbow is chief executive of the charity ADDISS (The National Attention Deficit Disorder Information and Support Service), which helps families affected by the condition. ADHD, she says, “is not about a badly behaved child”.
She adds: “It’s about a problem in the brain which means a child can’t regulate their behaviour or emotion. They don’t learn from their mistakes and they can’t plan or organise, and they have difficulties with their short-term memory.
“The bad-behaviour label is just used by people who don’t have a clue.”
ADHD Genetics Expert Weighs In
I know my limits in explaining complex research. So, I found a qualified expert to do the honors. She is a respected neurologist with significant background in ADHD research.
Her research institution, however, requires that all information provided to the media be cleared with the press office. I am sharing her comments, with her consent but without her name.
The published paper is reporting a genetic association between ADHD and abnormalities in CNV in some areas of the genome that have been previously associated with autism and schizophrenia.
“ADHD With Intellectual Disabilities”
The ADHD genetic expert first points out that the study subjects did not have typical ADHD but ADHD with intellectual disabilities.
- The main association is found in a group of patients that the authors define as “ADHD with intellectual disabilities.” That is, those patients have an IQ ranging from 43 to 69 (or less than 70). Those IQ scores fall in the range of Mental Retardation definition.
- By definition, typical ADHD children do not have mental retardation. It is necessary to rule out the presence of mental retardation as part of the exclusion criteria for the diagnosis of ADHD. When we compare typical ADHD children with mentally retarded children with ADHD symptoms, the comparisons are not appropriate. Those are phenotypically different conditions.
- There is no information about other medical problems, such as prematurity at birth, in the studied population. Those factors may produce “ADHD symptoms.” Yet, those are different etiologies from “typical ADHD.”
ADHD Genetic Association: Thirty Years of Evidence
- The paper has been presented as the “first evidence of genetic association in ADHD.” I think that this is not a true statement or is at least a misinterpretation. During the last 30 years at least, we have accumulated evidence of genetic association in ADHD by many sources. This current discussion about ADHD involves understanding the genetic mechanism that interacts with the environment to modify the clinical expression in ADHD. The genetic component is no longer a part of the discussion. The concept of ADHD as a social construct is no longer a part of biological research.
- The association with mutations is interesting, probably the first association with a “mutation.” As the authors state, however, these mutations are rare and probably will explain a very small number of ADHD cases. DNA mutations have been found more frequently in mental retardation in many studies. Clinical characterization of ADHD symptoms and exclusion of conditions that may mimic ADHD is very important to validate any biological or molecular finding. Otherwise, it is difficult to conclude that the findings are applicable to the population that we want to target, in this case, ADHD.
In Summary: Two Major Problems
In summary, I see two primary problems with this research as well as the reporting of it:
- The methodology that includes patients with mental retardation (that’s the scientific term) as a part of the diagnosis of ADHD.
- The interpretation of the press release as the “first evidence” of the genetic link to ADHD and the “evidence of biological correlations between schizophrenia and autism. I am really concerned about those statements. ADHD may many times mimic, overlap, or resemble autism or schizophrenia but they are not exchangeable conditions.