Is there any evidence ADHD is genetic? The only connection I've read about is that parents who are diagnosed with ADHD are more likely to have their children diagnosed with it, but that itself is not evidence of a genetic trait. Seems just as likely to be nurture than nature to me- for example if parents over-stimulate their kids by putting them in front of TVs/iPads/etc. from a young age it's not surprising they'll develop attention problems
> Is there any evidence ADHD is genetic? The only connection I've read about is that parents who are diagnosed with ADHD are more likely to have their children diagnosed with it, but that itself is not evidence of a genetic trait.
Short answer: yes, there's lots of evidence of genetic factors. One reason this isn't better understood is that a close relative can have undiagnosed ADHD, so people don't see the family ties. And also because it's stigmatized in some families, it's like a "don't ask, don't tell" situation.
I mentioned a great podcast by Dr. Andrew Huberman, a Stanford neuroscientist earlier in the thread that mentions how the genetics of ADHD works [1]:
How can those studies prove it is genetic if there is no quantitative way to diagnose it? If you could do a blood test or brain scan and make a diagnosis on physical data then sure, but until then it's all just conjecture
> How can those studies prove it is genetic if there is no quantitative way to diagnose it? If you could do a blood test or brain scan and make a diagnosis on physical data then sure, but until then it's all just conjecture
It's quite arrogant to suggest that an ADHD diagnosis is speculative or some kind of guess. It's thinking like this that causes people to not seek help or talk openly with family, friends and co-workers if they've been diagnosed with ADHD.
Psychiatrists are medical doctors who can make a diagnosis based on clinically accepted criteria of what constitutes ADHD and other mental health and neurological issues. There are lots of mental health conditions and disorders that don't have a blood test or brain scan that "proves" someone has that condition.
Brain scans do show differences between people with and without ADHD, but most of the time, you aren't going to get a $5000 brain scan (or whatever it might cost even if insurance pays for it) to diagnose something that's been in the medical literature for over 100 years when it can be diagnosed more conventionally and at less cost.
Turns out brain scans aren't 100% accurate and there are trade-offs [1]:
Brain imaging scans may be appealing because they appear to offer a firm diagnosis. However, these tests are still new in regards to their use in ADHD, and they have many limitations. These tests are also expensive and can potentially expose children to radiation.
Currently, brain scans are more useful for research purposes than for making clinical diagnoses.
ADHD isn't just one thing; there are subtypes where certain symptoms are more prominent than others.
Because the heritability of ADHD is 74% [2], I wouldn't be surprised that one day we'll have a genetic test that can help diagnose ADHD but we aren't there yet.
Definitely a lot of study in this, and much of it has shown there is a very strong sign that it is genetic and inheritable. As others have mentioned, twin studies and family studies have strongly supported a genetic component.
Doesn't mean there isn't also some nuture involved also, likely not the "over-stimulation" argument you make, but more likely the "if you have it, more likely to recognize it in your children" type of thing.
From the following link
> Decades of research show that genes play an vital role in the etiology of attention deficit hyperactivity disorder (ADHD) and its comorbidity with other disorders. Family, twin, and adoption studies show that ADHD runs in families. ADHD’s high heritability of 74% motivated the search for ADHD susceptibility genes. Genetic linkage studies show that the effects of DNA risk variants on ADHD must, individually, be very small. Genome-wide association studies (GWAS) have implicated several genetic loci at the genome-wide level of statistical significance. These studies also show that about a third of ADHD’s heritability is due to a polygenic component comprising many common variants each having small effects.
> Family, twin, and adoption studies provide a firm foundation for asserting that genes are involved in the etiology of ADHD.
> Adoption studies suggest that the familial factors of ADHD are attributable to genetic factors rather than shared environmental factors
> A similar heritability estimate of around 80% was seen in a study of MZ and DZ twins, full siblings, and maternal and paternal half-siblings
> There can be no doubt that DNA variants in genes or regulatory regions increase the risk for ADHD. In rare cases, a single genetic defect may lead to ADHD in the absence of other DNA variants. We do not know how many of these rare variants exist or if such variants require environmental triggers for ADHD to emerge. It is equally clear that no common DNA variants are necessary and sufficient causes of ADHD.
It doesn't preclude environmental factors either:
> The convincing evidence for genes as risk factors for ADHD does not exclude the environment as a source of etiology. The fact that twin estimates of heritability are less than 100% asserts quite strongly that environmental factors must be involved. ADHD’s heritability is high, and that estimate encompasses gene by environment interaction.
