Attention-deficit/hyperactivity disorder (ADHD) is a genetic, neurodevelopmental disorder and not just a behavioral problem. In a study published online in the Sept. 30 issue of The Lancet, investigators from the University of Cardiff in the United Kingdom say their findings show that ADHD has a genetic basis. In the genome-wide analysis, 366 children 5 to 17 years of age who met diagnostic criteria for ADHD but not schizophrenia or autism and 1047 matched controls without the condition were included. Researchers found that compared with the control group without ADHD, children with the disorder were twice as likely — approximately 15% vs. 7% — to have copy number variants (CNVs). CNVs are sections of the genome in which there are variations from the usual 2 copies of each chromosome, such that some individuals will carry just 1 (a deletion) and others will have 3 or more (duplications).
The breakthrough results of this study should help in the controversy as to whether ADHD is a "real disorder" or simply the result of bad parenting, in shifting public perception about ADHD and promoting further research into the biological basis of the disorder with a view to developing better, more effective therapies for affected individuals.