The obvious answer is that in America drugs are advertised on TV, and if you see a lot of ads for ADHD medication you might be more aware of the possibility tha

The obvious answer is that in America drugs are advertised on TV, and if you see a lot of ads for ADHD medication you might be more aware of the possibility that you have ADHD, and it could be normalised. After all the stereotype of American zombie kids on Ritalin was being bandied about 10-20 years ago? Whereas ADHD is still relatively not well known in most European countries. The UK was the same for autism about 10-15 years ago, it was barely talked about, now every class has 10-20% children diagnosed with autism and we have autism-friendly hours in cinemas/shops etc, nobody blinks an eye if you go out wearing big headphones etc. The same may happen for adult ADHD too.