I mean ~80% of the world's population takes stimulants daily in the form of caffeine. Childhood ADHD rates are now at ~12%, and the testing criteria for ADHD revolves largely around whether it negatively impacts your life.

If everyone else is increasingly taking stimulants for it and you're not, then you're more likely to feel negatively impacted since you'll stand out, which is likely to increase the diagnosis rate further.

I don't think it's unlikely that we see a world where like half the population has an ADHD diagnosis, and/or the treatment for ADHD (i.e. more effective stimulants then caffeine), become over the counter.