[galangalalgol]

The current estimate is more like 10%. Some of that may be over diagnosis, but some of it always was, kids have energy, that makes adults tired. But the degree of increase far exceeds any such explanation. The podcasts I've heard lately seem to indicate links to all the normal suspects, gut biome, autoimmune, and some chemical we may now be exposed to. Probably some combination.

Also, there are some jobs someone with ADHD will have a lot of trouble keeping. Jobs that benefit from hyperfocus are not among them. Many therapists will suggest careers like engineering, tech or writer (perhaps technical) for precisely that reason. So you would expect highly elevated rates of ADHD in those fields.