I have done two self-studies where I compared similar day’s work on meds and another off. I have done this twice, once in college (’90’s) and once in the 2010’s at work.
I consistently came in 6 times more productive on meds than off.
I must also state that my first MD was very systematic in his approach.
Instead of guessing a good initial dose for me, we started in 5mg of methylphenidate and slowly increased.
I kept a daily log of my blood pressure, good things, and side-effects.
We did three weeks at 5mg, 3 weeks at 10mg, 3 weeks at 15mg, started 3 weeks at 20mg – had side-effects – I called the office and 15mg became my prescribed dose at the time. The technical term for this is “titrating.”
I love that my MD did it this way.