Hello everybody, Russ Barkley here, and in this video I want to tackle a very serious topic that has been proposed by a family physician out of Canada, also a celebrity by the name of Gabor Maté. Dr. Maté has proposed that ADHD arises as a result of childhood stressful and traumatic experiences, what we would think of as adverse childhood experiences. This is his website. If you're interested, I'll put the link over in the thumbnail sketch.
And over here at Wikipedia, we can see that he got his degree in family medicine, general family practice, in 1977 at the University of British Columbia. And he then operated in a private practice in the city of Vancouver for many years. Dr. Matej has written a number of books dealing with addiction, stress, trauma, but specifically his book, Scattered Minds, is his book about the origins and healing of ADHD.
In this book and in his lectures, he is claiming that it is childhood adverse events and trauma that are the principal cause of ADHD. He goes on to elaborate that, This trauma can actually be transmitted cross-generationally from the parent's generation to the child. Then in addition, the culture can generate and transmit trauma to individuals. So according to Dr. Mattei, there's trauma everywhere and a lot of the problems we are dealing with in life and specifically ADHD specifically, appears to arise out of these adverse...
experiences in life. Now, it's interesting that Dr. Matej doesn't really define exactly what he means by trauma. It could be something as simple as an insult or an unkind word to somebody that someone takes offensively. As you know, the word trauma has been abused badly in our culture to mean just about anything that the person finds unwanted or unhelpful.
or adverse, but it could also go all the way up to the types of trauma that most people think about, which is physical trauma, witnessing violence, experiencing violence, and so on. And so it's difficult to say which of these mechanisms he is arguing for in ADHD. So we're just going to wind up rolling it all into the term adverse childhood events and let it go at that.
Dr. Mattei has appeared on the Joe Rogan Experience, in which he has articulated these ideas about stress and trauma being the principal cause of ADHD. On the show, the link to which is in the thumbnail sketch, Dr. Mattei claims that ADHD is not genetic, that it's not inherited, and that it is due to this within-generation and cross-generation adverse events. trauma, as he calls it.
He also has made the same remarks in another video that is posted over at the Norwegian Institute for Trauma, and you can find a number of other interviews on the internet where he has made precisely the same claims. I'm not going to take time to play these particular interviews or comments. We just don't have the time for that. You can go and find them yourself.
Here we're going to specifically look at this claim about ADHD being associated with traumatic events and not being genetic. So first of all, let me bring up a major review of the genetics of ADHD published in Molecular Psychiatry by my good friend Steve Ferone along with Heinrich Larson. And Dr. Ferone is probably the leading scientist in the world on ADHD having published... hundreds of articles on this topic throughout his lengthy and distinguished career. In this review of the genetics of ADHD, as he says, ADHD has a high heritability, 74%.
What does that mean? It means that the vast majority of variation in the human population in degree of ADHD symptoms is driven by differences in genetics. and genetic architecture.
Not by the environment, not by parenting, by genetics. That's what heritability means. Now, in a subsequent review for clinicians that was published over in the journal Current Psychiatry Reports, we have an article that was written by Oliver Grimm and others trying to reduce all of the genetic research, the hundreds and hundreds of studies on genetics, down to what clinicians need to know. And as you can see here, these authors...
tell clinicians that the formal heritability of ADHD is about 80 percent. So very similar to Ferron's conclusions that the vast majority of individual differences in the human population in degree of ADHD symptoms is determined by genetic differences. Now it's not just these people saying this, but the fact that we have experts in the field who are themselves experts in the genetics of ADHD, telling us that the majority of variants is due to genetics, immediately disproves Dr. Matei's thesis that ADHD is not genetic and is due to trauma. We could stop here, end this video.
Matei is wrong. He is worse than wrong. Worse than wrong means that, while you could be wrong about a particular idea, we go out and research it and we find that one person's right.
and one person's wrong when it comes to the results. Worse than wrong means that you continue to adhere and advocate a thesis that has been resoundingly refuted in the scientific literature. Why are you worse than wrong?
Because you are propounding nonsense. You are transmitting information that is grossly inaccurate, and in doing so, you are causing harm. Now, let's take a look at another paper.
This is a meta-analysis of the degree of genetic and environmental influences on ADHD symptoms. It was published by Molly Nicholas. It was published back in 2010, but there have been many, many more studies since then and other meta-analyses. But let's just take a look at this one. This is a review and combination of 79 separate studies of twins and adopters.
in which they examined degree of inattention, hyperactivity, and impulsivity. And then they took the results of at least 13 of these large-scale studies and did mathematics on them to calculate heritability. And what do these studies come up with? Exactly what Ferron and others have argued in those reviews. ADHD is accounted for by genetic factors.
with the heritability being about 71 to 73 percent. Now, that was 13 years ago. We have even more studies. So let me just emphasize this.
This review shows that not only is Dr. Matej wrong, he is wrong 79 times in the literature. His idea has been refuted by studies of twins and adoptees regarding the role of genetics. in influencing human variation on ADHD. Again, we could just stop here.
Maté is so wrong, he's worse than wrong. He is propounding what I have called nonsense on stilts. It has no empirical basis in the scientific literature.
But wait, there's more. Let's go further and take a look at some other studies here. This one on the role of the genetic determinants. of exposure to adversity among youth with mental illness. So this is a large study of children between 5 and all the way up to 27 years of age, and they looked at the offspring of parents with various disorders, mood, psychosis, anxiety, and ADHD, and they looked at the extent to which polygenic risk scores for certain traits, including ADHD, predicted exposure to adverse childhood events.
And what did they find? ADHD was the big one. ADHD polygenic risk scores uniquely explained variance in the adversity score, meaning... that the more ADHD risk genes you had, the more severe your ADHD was, the greater the likelihood you were going to be exposed to adverse childhood events.
So we can see here that the genetics of the disorder is driving the severity of the disorder, is driving the risk for adverse events both currently and later in life. We know this to be true, that having ADHD sets you up for a variety of adverse outcomes as a result of your symptoms and risk-taking and limited self-regulation and poor executive functioning. And these adverse events, as you've seen in many of my videos, span the whole range of social, familial, educational, occupational, sexual, substance use disorders, and so on and so on. All of these adversities are related to ADHD.
severity. So it's not hard for us to understand that people with ADHD are going to experience a lot more adverse events in their life than our typical people. Now, let's take a look at another study here.
This one is on the role of ADHD and the risk for later adverse events in childhood. And again, what does it find? It finds that at time one, ADHD individuals had a high probability of experiencing adverse events both at time one and later at time two. So ADHD, to start with, is predicting downstream risk for adverse events in life. Precisely the point that I was making earlier about all of the adversities that link up with ADHD.
Now... Finally, let's take a look at where some of this adverse experiences may be coming from. Here is a study, a very large study, of 22,000 parents and 11,500 of their offspring. This is a study of twins and siblings that took place in Norway. So it's a huge study, and it's looking at the cross-generational transmission of risk for ADHD.
And of course, what it is showing... is that the transmission is largely genetic, not environmental. I want to emphasize that. Once again, we have a study among many studies showing that ADHD is not the result of within family environmental factors. However, unique events out of family experiences may well contribute to some extent to ADHD.
I've talked about that previously. That can be anything from... birth complications, premature delivery, low birth weight, being exposed to alcohol in utero during that pregnancy, later on exposure to lead poisoning, traumatic brain injuries, and so on, all of which rack up in life and can contribute to risk for ADHD.
So there are a wide array of unique events that can produce neurological injury leading to an ADHD phenotype. that is not genetic, but is environmental, but not due to the social environment. We know that the family environment from these various studies contributes very little, if anything, to variation in ADHD.
So how can we summarize all of this research? And there are many, many, many studies that I could have cited here to prove once again that Dr. Matei and his thesis are... Wrong and worse than wrong.
But let's kind of wrap it up here with a graphic to kind of summarize for you very quickly what we think is going on here. So we have this thesis of Dr. Matej's that trauma in childhood, forget about the generational transmission of trauma, just trauma in childhood leads to ADHD and symptom severity. That's Matej's claim.
I have now shown you that many, many times over across the various research studies, MATE is wrong. There is a relationship between ADHD and adverse childhood experiences, but one cannot conclude that those adverse events by themselves are causal of ADHD. The fact that two things are correlated, as you know, does not mean they are causal. it can easily go the other way around from the one that Maté wants to propose here. So correlation does not mean causation.
And that seems to be what Maté is falling for here, is correlation as cause. Now, when we look across time at longitudinal studies, what we see is that future adverse childhood experiences are directly predicted by the severity of ADHD and even by the number of genes that predispose to ADHD in those individuals. So there is strong evidence.
that ADHD puts people at risk for traumatic events. Now, there is also some evidence to suggest, a little bit of evidence, that there is a weak relationship between time-one adverse events and worsening your ADHD symptoms, particularly inattention. I would not be surprised to learn that having ADHD, experiencing adverse events, those adverse events can feed back to perhaps worsen your ADHD a little bit.
It's not causing the ADHD, but that doesn't mean it can't exacerbate it, particularly for symptoms of attention. And of course, we know that severity of ADHD at time one, because of genetics, predicts the continuing persistence of ADHD at time two in most individuals. So you see, it's a heck of a lot more complicated. than the simplistic ideas being promoted by Dr. Mattei. Now, more importantly, Dr. Mattei completely overlooks what is now becoming a well-established set of relationships here that further adds to our understanding of the association of ADHD with adverse events.
And that is parental ADHD and its underlying genetics. We know... that parental ADHD is the single biggest risk factor or predictor of a child having ADHD.
If the parent has a diagnosis, their offspring are eight times more likely to develop that disorder than the offspring of families that don't have ADHD. There is no bigger risk factor than that, showing the striking genetic contribution to this disorder. But wait!
There is more. We also know that parental ADHD and its underlying genetics can contribute to chaotic, unsystematic, adverse family ecologies. That's no surprise.
I've talked about it in my other lectures on this website. So adults with ADHD know that they don't manage households quite the way that typical families do. They try to, but there can be more chaos, less systematizing, a greater exposure to adverse events because of other family members having neurodivergent and mental disorders. And let's not forget, parental ADHD also links up with depression, anxiety, substance abuse, and other difficulties, all of which conspire to create a family environment that could be leading to more adverse events.
So that's a link that Dr. Mattei does not talk about at all, but which the research literature is continuing to affirm. So do you see how complicated things are? It's not this ridiculously simple and silly idea of trauma causes ADHD, and that answers the question. So I'm sorry. There is a whole suite of underlying genetic and environmental effects that are going on here that we need to appreciate if we're going to really scientifically understand this association of ADHD with adverse events.
So I hope that you can see from this diagram that the scientific literature paints a much, much more complex picture than the thesis of Dr. Mattei's. Now, one final comment here. Let's look at what Dr. Mattei is inferring.
Who is supposedly creating these adverse childhood traumatic experiences that are supposedly, according to him, causing ADHD? Well, largely it has to be the family, doesn't it? And largely, that has to be parents. And specifically, in this country anyway, we like to pick on mothers more than fathers since they continue. to carry a heavier burden of childcare.
So indirectly, what Mattei is doing is what Bruno Bettelheim did 50 to 60 years ago for autism and what researchers in ADHD were doing 50 years ago as well, blaming the parents. for the child's condition. And I don't mean the parent's genetics.
I mean the parent's parenting. Their behavior is what was creating this neurodevelopmental disorder. We know that's not true. We know it's been disproven many times for autism.
No one holds to that idea anymore that refrigerator, cold, uncaring, unloving mothers cause autism. And nor do we hold to that idea that bad parenting is creating ADHD. We disproved that 45 years ago in our research, but that's what Maté is inferring here.
He's parent bashing, he's family bashing, and it just won't sell. Unless, of course, you adhere to the subculture of victimization so common in our country that you're not responsible, it's all these adverse events that are leading you to have these problems. It's what your parents did to you. It's how other people have treated you. It just caters to a culture of victimhood.
Well, I'm sorry, our research literature just doesn't support these ideas about the role of parenting and childhood adversity causing ADHD. If anything, what we see is that having ADHD sets you up for many different opportunities. for experiencing adversity and even emotional trauma and especially physical trauma in your life. And that, yes, once experienced, that might make the ADHD symptoms a little worse, particularly in attention, but it doesn't cause them de novo. So thanks for joining me for this.
I hope you can see why Dr. Mattei is worse than wrong when it comes to his thesis. about ADHD arising from childhood adversity. So hope to see you again on another video. If you enjoy this content, please recommend us to others.
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