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CHICAGO: A genetic propensity for attention deficit hyperactivity
disorder (ADHD) may actually help people thrive in nomadic
environments, according to a study of Kenyan tribesmen published
Tuesday.
US 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 anthropology graduate at Northwestern University.
“This insight might allow us to begin to view
ADHD as not just a disease but something with adaptive
components.”
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.
-- AFP
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