ADHD: Was the condition a boon for our ancestors?

Hyperactivity, impulsivity and a skittish attention span — the symptoms of attention-deficit/hyperactivity disorder (ADHD) tend to be seen as a weakness or mental health condition that needs to be treated.

But ADHD also has advantages that have been scientifically investigated. People with ADHD are considered creative and dynamic, they are socially and emotionally competent and have high cognitive abilities.

And that's not all. In a new study, researchers at the University of Pennsylvania attempted to trace the origins of ADHD. Co-author David Barack writes on X: "ADHD and ADHD-like cognitive traits such as distractibility or impulsivity are widespread and often viewed in a negative light. But if truly negative, then their persistence presents a puzzle."

So is ADHD an important part of evolution? According to the new study, you could say so, yes. The research team said ADHD developed as an adaptive survival strategy for our ancestors. Their study was published in Proceedings of The Royal Society B (Biological Sciences).

Picking berries with ADHD

To get to the bottom of the matter, the researchers analyzed data from 457 adults, 206 of whom reported they had ADHD symptoms.

The test subjects were asked to collect as many berries as possible from virtual bushes in a video game, in a limited amount of time.

They had to decide again and again: Do they continue collecting in the same spot where the berries are running low or do they change locations to explore a new bush? The latter cost valuable seconds.

Those with ADHD traits tended to switch more quickly and spend less time on a single bush, effectively collecting more berries than the group without ADHD symptoms. The latter, in turn, tended to spend much more time on one bush in the hope of optimizing the yield.

The researchers were surprised by this result. They assumed that the rapid change of shrubs would lead to a poorer yield. "But higher ADHD symptoms lead to a higher reward rate and better performance," said Barack.

ADHD as a survival strategy

This tactic has its advantages: it prevents the exploitation of resources in a single location, while at the same time new areas are scouted — a strategy that may have been vital for the survival of hunter-gatherers in the past.

Other studies support this evolutionary advantage thesis. They have shown that a nomadic lifestyle is associated with genetic mutations that play a role in ADHD.

All of this could possibly explain why ADHD is so prevalent today — the difference being now that traits that used to prove their worth in foraging are no longer quite as advantageous in contemporary society, at least where resources are plentiful.

Dopamine is broken down more quickly in people with ADHD than in people without it. The constant striving for this important neurotransmitter can lead to people with ADHD to constantly switch back and forth between different tasks without really completing one.

However, the researchers emphasized the need for further investigations because, they said, the significance of their study is limited to the participants' self-assessment of their ADHD.

In a next step, the researchers want to conduct a study with people who have been diagnosed as having ADHD, as opposed to those with a self-diagnosis. In addition, they will set real-life foraging tasks, which require more effort than a virtual game.

Sources:

Attention deficits linked with proclivity to explore while foraging, Proceedings of the Royal Society B: Biological Sciences, 2024

A qualitative and quantitative study of self-reported positive characteristics of individuals with ADHD, Frontiers in Psychiatry 13, 2022

Dopamine receptor genetic polymorphisms and body composition in undernourished pastoralists: An exploration of nutrition indices among nomadic and recently settled Ariaal men of northern Kenya, BMC Evolutionary Biology 8, 2008

This article was originally written in German.