Did Our Ancestors Have ADHD?

In Back to Normal, psychologist Enrico Gnaulati considers the over-diagnosis of conditions like ADHD, biopolar disorder, and autism spectrum disorders. Amanda Schaffer finds some of his arguments “compelling” but sees in Gnaulati “a tendency to reach beyond the evidence”:

In particular, he resurrects an old evolutionary claim, popularized in the 1990s. The idea is that “A.D.H.D. traits such as distractibility, impulsivity and aggressiveness,” which today can be maladaptive, helped our hunter-gatherer ancestors to survive. “Restlessness, constant visual scanning, and being amped up for quick and aggressive action happen to be attributes of fine hunters,” Gnaulati writes. “If Ritalin had been around 150,000 years ago and taken in mass quantities, our survival as a species might have been uncertain.”

Well, maybe. Speculating about what life might have been like for our ancestors, what traits aided their survival and whether the genetic underpinnings of those traits remain in tact today is a dicey proposition.

Gnaulati does cite one study of Kenyan men, some of whom have a particular genetic variant associated with A.D.H.D. Among the men who were nomadic, having this variant was linked to being “more physically nourished.” Among the men who were recently settled, the reverse was true, which Gnaulati interprets to mean: “A.D.H.D. actuality gives you a leg up under nomadic conditions when you have to forage and hunt but acts as a hindrance when you have to slow down and plow the soil.” The gene variant in question, however, is only weakly linked to A.D.H.D. In fact, most people with this variant do not have the disorder, according to Joel Nigg of Oregon Health and Science University. That makes it tough to generalize about A.D.H.D. based on these men.

Also, as far as common sense goes, doesn’t hunting actually require patience, planning and self-control? Would you trust the survival of the species to an A.D.H.D. kid armed with a spear?