Mad medicine was everywhere in the 80s and 90s. There were toys and playsets endorsed by mad doctors, for use by kids. Every time you watched cartoons, you saw a skinny dude with crazy hair in a white lab coat, maniacally mixing chemicals and potions for some nefarious purpose. Under the influence of this, I created my own mad medicine man; Dr. Kill-Everybody.
Either the trope became shopworn around 2001, or something happened that discouraged children from playing with chemicals. You don’t see mad doctors and scientists like you used to. Maybe this is a good thing; maybe the concept was subconsciously driving impressionable kids away from lucrative STEM-field careers. I don’t know.
What I do know is this. Mad doctors once flourished in our society, even though they were annoying, and generally sucked.