Vindicated! ADHD is an Evolutionary Success
Hunters of the world, rejoice! We’re not defective; we’re just different — and different in a way that can be incredibly useful and helped the human race survive for millennia!
Back in 1980, when I was the Executive Director of a residential treatment facility for severely abused and “disordered” children, I published in The Journal of Orthomolecular Psychiatry one of the first papers on diet and what was then called the Hyperactive Syndrome or Hyperkenisis, later called Attention Deficit Disorder (ADD), and now called Attention Deficit Hyperactive Disorder (ADHD).
We’d done a six-month trial of the Feingold diet and found that it only worked at reducing figityness for one of our kids, and he had severe eczema which was aggravated by the food additives Dr. Feingold had identified as possible allergens.
That realization — that ADHD wasn’t “caused” by something but is, instead, a set of traits, characteristics, skills, and weaknesses that we inherit from our parents — led me to conclude that it must have some value to have persisted all these hundreds of thousands of years in the human genome.
That value, I concluded, was probably a time in human pre-history when we lived as hunter-gatherers. But what value would the hallmark characteristics of ADHD — distractability, impulsivity, and a need for high levels of stimulation — offer to primitive hunting gathering people?
Distractability, I concluded, would mean a Hunter was better at scanning his or her environment. Impulsivity would help when making split-second decisions in a wild, wild world. And a love of high levels of stimulation would propel people out into the field, jungle, or forest to hunt things that might want to eat humans as much as they wanted to kill and hunt them.
In 1996 I rolled this theory out with a book that’s still in print (after being updated repeatedly) titled ADHD: Hunter in a Farmer’s World. TIME magazine wrote it up and that kicked off what has since become an international controversy.
Some agreed with me. Harvard professors John Ratey and Edward Hallowell wrote the forewords to two of my books and blurbed others. Russell Barkley, on the other hand, ridiculed my theory, pointing to his own brother who had ADHD and was apparently, from Barkley’s point of view, a failure in life (“Mom liked you more”?).
Now, 28 years later, science has caught up with my hypothesis.
This week a new paper was published by The Proceedings of the Royal Society, Biological Sciences titled “Attention deficits linked with proclivity to explore while foraging.”
In it, the researchers at two Pennsylvania universities (one a medical school) and a scientist in India concluded that, yes, these characteristics can demonstrably improve the success for people foraging in ways similar to what humans experienced more than ten thousand years ago.
In their paper, they note:
“In humans, nomadic lifestyles favouring exploration have been associated with genetic mutations implicated in attention deficit hyperactivity disorder (ADHD), inviting the hypothesis that this condition may impact foraging decisions in the general population.”
They recruited over 450 individuals and set them about the task of trying to extract as many berries as possible from a cluster of berry patches. People were free to use any strategy they wanted: exhaust all the berries on one plant before moving on to the next, just grabbing the easiest ones to get before moving on to the next plant, or any sort of variation in between.
The researchers then scored all the study participants on traits associated with ADHD. And, surprise of surprises, they discovered that the people with the most ADHD traits had the greatest success in collecting the largest quantity of berries in the shortest period of time!
Breaking it down in the language of science, they concluded:
“Higher reward rates in ADHD screen-positive participants may reflect adaptive specialization in the capacity to focus. Attention is known to be regulated in part by dopaminergic receptors and transporters [63,64]. Animal models of ADHD show dopaminergic deficits in the basal ganglia and prefrontal cortex [65], and both the D2 [66] and the D4 [67] dopamine receptors are associated with ADHD.
“These same receptors are implicated in differences in nutrition and health in comparisons of nomadic and settled populations [27]; specifically, the interaction between lifestyle and allele length for the D4 receptor predicts healthier body mass. Longer alleles for the D4 receptor are a risk factor for ADHD [67].
“Taken together, allele length for the D4 receptor is a risk factor for ADHD and correlates with better nutritive outcomes in nomadic populations. Consistent with our reported findings, we speculate that ADHD serves as an adaptive specialization for foraging [68–71], thus explaining its widespread prevalence and continued persistence in the human population.
“Individuals with ADHD may be more reward-seeking, consistent with the role of dopamine in motivated behaviour [72] as well as heightened impulsivity on delayed discounting tasks [73].
“Individuals with ADHD may also be more exploratory as a result of increased noradrenergic drive originating in the locus coeruleus and broadcast to prefrontal cortex [29]. Typical individuals, by contrast, may be driven by a variety of motivations, including gathering more information about the environment through persistent foraging.”
Having endured years of harassment and name-calling from high-profile “experts” in the ADHD field, this feels very much like a vindication.
As one headline about the study reported: “ADHD may have been an evolutionary advantage, research suggests.”
Of course, we no longer live in a hunter-gatherer world, so ADHD can be a very real challenge for many children and adults.
On the other hand, we can reorganize our schools to be more ADHD-friendly (as I wrote about earlier), and adults can choose professions or jobs that are filled with variety and excitement to satisfy their needs for stimulation and novelty.
Hunters of the world, rejoice! We’re not defective; we’re just different — and different in a way that are often incredibly useful and helped the human race survive for millennia!
I am more interested in comparing the driving records of persons with ADHD with persons without, especially those that drive on freeways every day.
I am sure there are actuarial studies that compare health and accident outcomes of those diagnosed with ADHD and the population not diagnosed. The insurance industry has tons of data.