Not disagreeing with you because I don't know for sure, but I once read she was put on benzedrine to help her control her weight and that was how she got hooked.
About Rooney, it appears when he was 19 he had a torrid affair with 39 year old Norma Shearer, at the time a major actress at MGM. It didn't last long. (1940s)
That’s probably true.
The studio executives turned her into a walking apothecary.
yes, they were concerned about her weight and got her on pills. She also came from a dysfunctional family. Her father had “issues” to put it nicely. And Mickey Rooney slept with anyone from what I have read.