“By the time I got to medical school, no one even talked about it,” Ross said.
Besides, substance abuse programs focus heavily on the current headliner addiction drugs - opium in the late 19th century, alcohol in prohibition times, cocaine in the 80s, crack thereafter, prescription painkillers and heroin again now; with a secondary focus on whatever's not the current headliner. How many recent (or non-recent) news stories are there about an epidemic of LSD addicts or mushroom addicts?
Kind of like asking how someone gets to be a web developer without being fluent in Fortran and COBOL.