CAUSES OF ADHD
Recently a study appeared showing that a common drug used in treatment of diabetes was a risk factor for ADHD in pregnant mothers taking the drug compared to mothers with diabetes but not taking the drug.
In mothers treated with antidiabetic medication (n = 7479), there was a small but significant increased risk of ADHD (HR, 1.20, adjusted to 1.16; P = .03), compared with children from mothers with diabetes [gestational or type 2 diabetes] who did not take the drug.
A journalist dismissed the importance of this effect on the overall prevalence of ADHD: "the increased risk for this (presumably) very small group of women can't have that much effect on the ultimate numerator of ADHD."
I believe this response may reflect the common assertion that most of the elevated prevalence is due to non medical factors such as pressure from pharmaceutical companies.
While partially true, the assertion incorrectly dismisses the relevance of multiple medical causes of ADHD. As I responded, "The numerator for prevalence of ADHD may be small but it shows how a particular causative effect is in play, along with numerous other pre and perinatal causes. I would count it in toto to be highly significant. We don't know the impact of numerous other pills being ingested by pregnant women. Samples of numerous pills are found in large swaths of waste water in the country."
To this must be added known risks of ADHD from organophosphate pesticides, lead in house paint & drinking water; low birth weight; brain trauma from a variety of sources, including infectious, radiologic, or immunologic factors in prenatal or perinatal environments.
In other words, ADHD has many causes related to early neurodevelopment, as well as the well-established hereditary or temperament causes. It is important to beware of "simple & sovereign theories," as Gordon Allport warned long ago.