Oct. 27, 1999 (Chicago) -- Research into the genetic causes of attention deficit/hyperactivity disorder (ADHD) has not yet unearthed one particular gene that triggers the condition, according to Stephen V. Faraone, PhD, who spoke here recently at the 46th Annual Meeting of the American Academy of Child and Adolescent Psychiatry. However, there may be several genes that, when combined, increase a child's risk of having ADHD.
"ADHD runs in families, and that may be in part due to genes that we call 'susceptibility genes' because they only make people susceptible to a condition," Faraone tells WebMD. "Eventually this research may help us identify children at risk of ADHD, so that parents can modify the child's environment, but we have to find the genes first." Faraone is an associate professor of psychiatry at Harvard Medical School and Massachusetts General Hospital in Boston.
Investigators became interested in finding a possible genetic basis for ADHD after observing that it was familial and after finding the genetic basis of several other conditions, ranging from Alzheimer's disease to certain forms of breast cancer, says Faraone.
"We spent 50 years blaming the mothers of ADHD children, and that was appalling," Michael Fitzgerald, MD, tells WebMD. "We are now moving to a more holistic perspective, and we see that several genes may have a strong role in causing the condition. ... In 10 years' time, we may be able to confirm that a child has ADHD by a laboratory DNA test, and get treatment started earlier."
Fitzgerald, a professor of psychiatry at Trinity College in Dublin, Ireland, co-authored a study presented here. He and his colleagues found that two particular genes were more likely to appear in the DNA of children with ADHD and their parents. That likelihood was increased if the parent also had ADHD. Other studies presented here further validated the genetic link in ADHD.
"There seems to be a high genetic component to ADHD," Pierandrea Muglia, MD, who presented genetic research, tells WebMD. "However, it's probably a complex relationship between several genes." Muglia is a staff psychiatrist at the neurogenetics section of Canada's Center of Addiction and Mental Health in Toronto.
"Discoveries in molecular genetics may put child psychiatry on the precipice of a revolution," Alan Zametkin, MD, tells WebMD in an interview seeking objective analysis of the latest genetic research. "We have no findings regarding the genetics of ADHD that affect its diagnosis and treatment yet, and we should not expect to see any such findings within the next couple of years. However, five years or so from now, studies that are ongoing now could lead to such breakthroughs."
The meeting was held in conjunction with the 16th annual meeting of the Canadian Academy of Child Psychiatry.