By Randy Hecht | Posted January 17 2011
Researchers in Wales find evidence of a genetic link
In the past, it’s sometimes been dismissed as bad behavior or blamed on poor parenting. But new research suggests that Attention Deficit Hyperactivity Disorder—ADHD—may be caused in part by a genetic anomaly.
Dr. Nigel Williams of the MRC Centre for Neuropsychiatric Genetics & Genomics at Cardiff University School of Medicine led the team whose study was published in The Lancet this fall. (An abstract is available here; registration is required to access the full article.) Team member Dr. Anita Thapar, Professor of Child and Adolescent Psychiatry, explains: “Our study looked at one type of genetic variation, DNA duplications and deletions known as copy number variants (CNVs), [which] have previously been implicated in brain disorders such as autism, schizophrenia and mental retardation.”
“We identified a highly significant excess of large, rare CNVs in children with ADHD compared with control participants, with the average number of CNVs per child with ADHD being 2·09 times higher than that in controls,” the team reported. “Our findings provide genetic evidence of an increased rate of large CNVs in individuals with ADHD and suggest that ADHD is not purely a social construct.”
Further research will be needed to establish the genetic link conclusively, and that research is expected to show that the genetic link is just one of several factors that can trigger incidence of ADHD. Scientists are reaching similar conclusions in research dedicated to establishing a genetic link to disorders such as schizophrenia and autism.
“ADHD, like other common disorders, is influenced by genes and environment,” Thapar says. “Genetics is not an either/or with behavior, psychology or environment.” But identifying the genetic markers can help scientists predict which people will be more susceptible to the other factors that, in combination, can cause ADHD.
How can establishing a genetic link help to refine treatment for a condition like ADHD? As research continues, Thapar says, new studies could point the way to novel therapies. Study results might also help to determine which treatment is best suited to a particular patient’s needs by taking into consideration the variety of factors, including genes that caused the condition in that patient.
CONNECT THE DOTS
The National Institute of Mental Health has created several downloadable guides to ADHD that are available in English and Spanish. Additional NIMH resources include ADHD videos, details of clinical trials, and information about where to go to seek help. The NIH offers a FAQ about genetic disorders and a Genetics Home Reference guide.
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