Study: ADHD gene may have helped early humans

A short attention span may not be conducive to learning in a

classroom, but it may be related to behavior that at one time helped

humans explore new environments and survive, according to UC Irvine

researchers.

The study, released last week, shows that a variant form of a gene

associated with attention deficit hyperactivity disorder (ADHD) indicates

that the disorder is a fairly recent condition and may once have helped

humans thrive.

Robert Moyzis, professor of biological chemistry, and his colleagues

studied genes from 600 people around the world. They found 56 variations

of a gene, one of which was strongly associated with the disorder.

This variation was created between 10,000 and 40,000 years ago and may

have provided an evolutionary advantage at some time in human history.

But the study could not determine if this evolutionary selection is still

occurring.

ADHD is the most common disorder in early childhood and affects about

3% of all elementary school children in the U.S. The condition is

characterized by developmentally inappropriate conduct, lack of attention

and impulsive and hyperactive behavior, which all usually occur before a

child becomes 7 years old.