It fries your dopamine receptors, this is drugs 101. Your are not going to take speed every day for years and function normally, and you will literally need confirmation bias to make sense of that reality.
Also, here is another weird tidbit from life. You might not like the stuff you used to like anymore but you won’t even know since you are sure it’s the disease.
Funny you should say that, as there is much research to say that ADHD is primarily a resistance to dopamine and serotonin. See: https://www.psychologytoday.com/us/blog/evolutionary-psychia...
This is how Ritalin works, by slowing down the reputable of dopamine.
So, imagine the state of anhedonia you’re familiar with from long-term drug abuse - then imagine that is your base state.
If you play games with this daily you will need to believe that all hard work should be primed with a natural feeling of euphoria.
If you start the kids on it that young, up the pressure, and put them in the same room where everyone else is doped up on it, I can promise you will cook an entire generation of knowledge workers by the time they are 30.