10 June 2008

Attention deficit disorder aided early humans

Agence France Presse
A genetic propensity for attention deficit hyperactivity disorder may actually help people thrive in nomadic environments, says a study of Kenyan tribesmen.
Nomadic tribesman

Hyperactive and useful: Is ADHD an advantage for nomadic tribesman today - and by extension our hunter-gatherer ancestors? Credit: Jason Radak

CHICAGO: A genetic propensity for attention deficit hyperactivity disorder may actually help people thrive in nomadic environments, says a study of Kenyan tribesmen.

U.S. researchers found that a gene associated with the disorder was linked to better health and body weight in a group of nomadic cattle herders, but could cause malnourishment in their cousins who have recently settled and begun to grow crops.

“Our findings suggest that some of the variety of personalities we see in people is evolutionarily helpful or detrimental, depending on the context,” said lead author Dan Eisenberg, an anthropologist at Northwestern University in Chicago, Illinois.

Useful trait

“This insight might allow us to begin to view ADHD as not just a disease but something with adaptive components,” he said.

The dopamine receptor gene Eisenberg and his team studied is involved in impulsivity, reward anticipation and addiction and is believed to be associated with food craving as well as ADHD.

The effects of these genes have been studied in industrial countries but little research has been carried out in subsistence environments which more closely mirror the environments where much of human genetic evolution took place.

“It is possible that in a nomadic setting, a boy with this allele might be able to more effectively defend livestock against raiders or locate food and water sources, but that the same tendencies might not be as beneficial in settled pursuits such as focusing in school, farming or selling goods,” Eisenberg said.

The study was published in the journal BMC Evolutionary Biology.

NEWSLETTER

Sign up to our free newsletter and have "This Week in Cosmos" delivered to your inbox every Monday.

>> More information
Latest
issue
CONNECT
Like us on Facebook
Follow @CosmosMagazine
Add Cosmos to your Google+ circles

Get a weekly dose of Cosmos delivered straight to your inbox!

  • The latest in science each week
  • All the updates on our new website launch
  • Exclusive offers and competitions

Enter your name and email address below: