I've never taken an art class in my life, but that never stopped my ADHD need to constantly doodle. The margins of ruled paper in various high school classes were often covered in eyes and cubes and stars and tornadoes, and sometimes more adolescent drawings if it was a dirty note being passed back and forth. University had less of the dirty stuff, but I still relied on minor mindless drawings to pay attention in class. But it was working in a call centre made my doodling habit especially bad; worse yet were the failed filmmakers and art school dropouts who worked alongside me and encouraged me to put my exceptionally absurd ideas on paper. I would call myself self-taught if I actually learned anything from it. I don't know if it's the change in complexity of my job, or the possession of a smartphone that has curbed my doodling in the workplace more. But, maybe having a place to put them will inspire me more.
I've divided the various things I've drawn into a few categories: