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.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477889/