Is ADHD Good for Something? ADHD as an Adaptation - Part II

In this two part video, I examine the hypothesis that ADHD is not a disorder but is simply a mismatch between modern culture and traits that were adaptive for some reason earlier in human evolution. This adaptationist or mis-match idea argues that cultural evolution proceeded far more quickly than biological evolution such that a trait or set of traits that were once adaptive or helpful to human survival in earlier periods of human evolution have become maladaptive due to changes in culture such that these traits are no longer adaptive. For example, Hartmann’s idea that ADHD represents earlier successful hunters during the hunter-gatherer phase of evolution now forced to live among farmers in contemporary culture. Or Jensen and colleagues’ idea that ADHD represents adaptive traits for warfare during an earlier human epoch that are new at odds with a relatively more peaceful contemporary culture.

Part I of this video examines these ideas as well as the evidence for the current known etiologies of ADHD to see how well they agree or disagree.

In Part II, I go on to explore an alternative, more scientifically based theory of ADHD as a set of maladaptive traits that can remain at a stable rate within a human population. This “conveyor belt” theory by Keller (2008) argues that new mutations arise all the time in the genes for ADHD (and other neurodevelopmental disorders) in each new generation and that it takes multiple generations for natural selection to remove those original mutations. Despite their being removed, new mutations continue to arise in the next generation that go on to create disorder. If the new mutation rate and the genetic removal (death) rates (natural selection) reach a certain level of balance with each other, the result is a stable rate of a maladaptive trait (disorder) within a population (say, 5-8%). The available evidence is more consistent with this theory than with the hypothesis of cultural mismatch.

Esteller-Culcala, P. et al. (2020). Genomic analysis of the natural history of attention-deficit/hyperactivity disorder using Neanderthal and ancient Homo Sapiens samples. Nature Research: Scientific Reports (10).

Hartmann, T. (1993). Attention deficit disorder: A different perspective. Novato, CA: Underwood Miller Press.

Jensen, P. S. et al. (1997). Evolution and revolution in child psychiatry: ADHD as a disorder of adaptation. Journal of the American Academy of Child and Adolescent Psychiatry, 36, 1672-1679.

Keller, M. C. (2008). The evolutionary persistence of genes that increase mental disorders risk. Curren

[fraufuchs]

"Natural selection has been acting against this genetic variants", it kind of hurts to know natural selection wants to get rid of me. On the other hand, I'm in my mid 30s and never had any addiction and I don't think I have any risky behavior. I guess I should call it a win.

[rskcy]

Just my thoughts as a biologist (with ADHD).
Even without the new mutations, as not all chidren of ADHD parents will be ADHD, but still carry some of the genetic variants, two people like this can have ADHD children without new mutations, adding to the stable rate.

The other thing is, success in a biological sense, has very little to do with life expectancy (after reaching reproductive age), and I would guess risky sexual behaviour is not a modern thing in ADHD, so I guess the rate of children/repro years might have been a bit higher for those with ADHD, making up a bit for the less repro years.

Until you showed the last paper, my first thought was WHY does everything has to be either adaptive or maladaptive? I can imagine a society/culture/time period, where mild to moderate ADHD would just be neutral, no selection for or against.

[Alex-kjrc]

Thanks for another amazing video. I really appreciate your communication style, very clear and concise. This is especially valuable when there's so much misinformation about ADHD around. Also, to let you know, I first realised I likely had ADHD when, around five years ago, I watched some of your older lectures on YouTube, which prompted me to seek treatment. So without the benefit of your work, I could easily have continued bumbling along undiagnosed and untreated, and I imagine there are thousands of people like me. You're one aging baby boomer who will continue to have relevance for many decades to come through the lives of people you've helped to understand their condition.

[jonsprivatelife]

'Relatively stable' is how my therapist describes me, hah. And as long as misinformation continues to be popularised, the relevance and necessity of channels like this one will never fade!

[phillustrator]

Thank you for these 2 videos. I think it's a bit of a missed opportunity that you did not address recent studies that support the adaptation hypothesis. For example: Swanepoel et al. (2022) found that in the sedentary population of the Ariaal tribe in Kenya, ADHDers were less well fed than the average, whereas in the nomadic portion of the tribe, they were better fed. This supports the hunter/farmer hypothesis.
Also: Chuansheng Chen et al (2011) found genetic evidence that ADHD was overrepresented in the early explorers that came out of Africa. Which suggests that ADHD helped humans colonize the planet, and encourages exploration and novelty seeking.
I believe balancing the views is more scientifically rigorous than focusing solely on the negative aspects.

[VitorFM]

Thank you for this video discussing the evolution of ADHD-associated alleles and its implications for the mismatch theory. While the video presents a compelling perspective, I would like to offer a more nuanced analysis:

1. *Lack of Disproof for Hunter-Farmer Theory*: The article's findings do not categorically disprove the Hunter-Farmer Theory. The data explores allele frequencies but does not directly address the adaptiveness or non-adaptiveness of ADHD in various historical contexts.

2. *Terminology: Fitted vs. Non-Fitted*:
- *Example*: Considering ADHD-associated traits as "fitted" or "non-fitted" to specific societal structures allows for a more complex understanding. For instance, impulsivity might be non-fitted in a structured classroom setting but fitted in creative or entrepreneurial endeavors.

3. *Complexity of ADHD's Evolutionary History*:
- *Kin Selection*: ADHD-associated traits might have enhanced the fitness of close relatives.
- *Frequency-Dependent Selection*: ADHD-associated traits might have been advantageous at specific population frequencies.
- *Heterozygote Advantage*: Carrying one copy of ADHD-associated alleles might have conferred benefits in certain environments.

4. *ADHD and Creativity*:

5. *Ethical Considerations*: Labeling ADHD as maladaptive may inadvertently lead to stigmatization or eugenics. A more balanced view is essential.

6. *Need for Further Research*:
- *Diverse Populations*: Future studies should explore how ADHD-associated alleles function across different cultural and genetic backgrounds.
- *Environmental Interactions*: Understanding how ADHD-associated genes interact with various environmental factors can provide a more comprehensive view of ADHD's evolutionary dynamics.
- *Group-Level Advantages*: Research into how ADHD-associated genes might confer advantages at the group level, such as fostering creativity or resilience within a community, could provide new insights.

In conclusion, while the video and the article contribute to an essential discussion on ADHD's evolutionary history, a more nuanced and scientifically rigorous approach is warranted. The use of terms like "fitted" and "non-fitted, " along with the consideration of alternative hypotheses and detailed examples, can foster a more robust understanding of this complex subject.

Thanks.

[Handle]

I appreciate that you tell us the truth, even when it’s painful to hear. As the parent to ADHD offspring, learning that nature is doing its best to cull these genes from from the population (even as new mutations pop up) is sobering. Parents who refuse to “drug” their ADHD children ought to consider that fact. Please continue to rage, rage for many years to come, Dr. B.

[AmandaJuneHagarty]

Also, i would just like to point out that it doesn't matter whether we were adapted for living in any specific past society or not. Because we are all adapting all the time, no matter what our genes. Those of us watching this video tonight are atill here because we had a challenge and we adapted and survived. Maybe some of us as individuals learn to be more creative in order to manage lifes little challenges. Some of us still win in the face of adversity. Just because these ideas that our ADHD makes us special arr not true, doesn't mean that we aren't each special as individuals because of the things we have faced and overcome.

[shaneward_adhdreimagined]

I think what is frustrating for me in this area is the level of certainty that is proposed to negate another certainty. It's not entirely true to suggest that modern evolutionary theory suggests that ADHD (or any other disorder) was good for anything - a fair amount of that thinking is legacy faddism (the 60's thinking that there is A gene for everything).

Let's be fair, the Esteller-Culcala, P. et al. doesn't conclusively close the door on anything, they're simply proposing an alternative analysis. In fact they don't completely discount the mismatch theory - but I'm not hanging my hats on any specific theory.

Why I am extremely sensitive on this particular topic is that to exclude the cultural/environmental impact altogether challenges our ability to influence our environment in a meaningful way. As a genetic "maladaptive" I can influence the environment that I work in to make it more beneficial to my employer and less strenuous on my efforts. It's about understanding

This is a complex topic with too many redirects - there are aspects of an ADHD diagnosis that rely on our interaction with our environment in order to determine an impairment, in another environment that diagnosis would not be made, and yet somehow we're still certain that ADHD is empirically defineable (notwithstanding the fact that the above study relies on existing ADHD diagnostic data to assume gene clusters are representative of a disorder determined via DSM criteria).

[u_js]

It seems that it's the gene pool that's adaptive through these intricate kill and spread mechanisms rather than the individuals. Maybe the gene pool wants us to spread more quickly with less thought... A fascinating 2 part series thank you.

[deltastripes]

14:50 - ohhh no, not clinging to relevance at all, you have improved the lives of countless people and your legacy will carry on for generations in waves of impact.

ADHDers around the world are so thankful for you to continue sharing your insights freely on the internet 🇰🇷

[IndyCookie]

14:46 the signoff on this video is hilarious. Russ really makes some of the best content out there.

[RyanFuruness]

Thank you so much for this, the internet contains way too high of a % of guru nonsense about ADHD and too low of a % of your content

[patriciajump]

Relevance! You got it! Thank you for your fascinating reports. This boomer very much appreciates them. Please keep them coming!

[BrothireStrangLuve]

Thank you very much! I'll watch this 4 times in a row to get a full hour of Barkley knowledge!

[antkcuck]

Thank you for your diligent work and clear presentations on this topic over the years

Your (in previous videos) explanation of the benefit of medication, especially the analogy to insulin for diabetes helped me to overcome hesitation, and to not be put off by well meaning but misinformed friends and family, and the medication has made a strong difference but I am still in strong deficit in many areas

I would love to see in-depth discussion/review for many different strategies for overcoming ADHD difficulties, possibly in detail for each executive disfunction.

I have an app on my phone that reads out the time in 15 minute intervals which is helpful

I make use of calendar and reminder apps

I try to budget my income but struggle to stick to a plan

I struggle with severe insomnia and unfortunately the medication is no help there

[chrishawkins]

Hey doc thanks so much for all this amazing content! I think you address the evolutionary adaptation idea very well. But I was wondering if you would be interested in doing a related but slightly different take on "Is ADHD good for something?", Which is - regardless of whether ADHD is evolutionarily advantageous, disadvantageous, or neutral - have you seen in any of your clinical work or research, any day-to-day benefits of ADHD in terms of living, working, creativity, sociality etc? I would love to see that.

Perhaps a more similarly related topic to this video is whether there is any evidence that ADHD could have benefits in terms of sexual selection? It seems to me that not only are of some of us ADHD'ers more prone to promiscuity and sexual impulsivity, but those ADHD personality-type traits can be...well, sexy! Asking as an ADHD father with an ADHD partner 😅 Thanks again

[HansBBJJ]

Dr Barkley, your last comment hit me like a train. I hope one day I too will say, "I am just an aging millennial reaching for continued relevance in late life."

Listening to you has been helping me make better life choices that hopefully will increase the odds of me growing into a riper age than statistically expected.

[elianmusic]

Thank you Dr. Barkley <3 Deeply appreciate your efforts and care. Love from Cairo, Egypt

[Alex-jslg]

Could impulsivity/lack of inhibition possibly be a factor as well? Those with lower capacity for self-regulation and planning presumably have more unplanned/unprotected sex which (I'd imagine) leads to more pregnancies and more children being born with a 50% chance of developing ADHD. Given how low general childhood mortality rates are, I could see something as seemingly inconsequential as that actually being enough to offset the increased risk of accidental death.

That would obviously depend on the specific numbers though: whether people with ADHD tend to have more children than those without and/or if they tend to have them earlier in life.