Substituted amphetamines were already very popular in the 1950s.
Methamphetamine was invented in Germany in 1937 and the German military at the time was very quick to adopt its use.
Everybody who could afford it adopted psychostimulants in WW2. Go pills have been part and parcel since then. Some countries have adopted modafinil, but the US still uses amphetamine.
I am an adult with ADHD and have never been able to get past the side effects that I have to drugs such as amphetamines and SSRIs. I was prescribed Modafinil for a short period for "Shift Work Disorder" when I worked shift work as a Stationary Engineer and it was glorious in regard to my ADHD symptoms with effectively zero side effects. I wish the US would expand its usage.