I think you're underselling the risks of prescription speed pills. Once you're getting a dopamine rush, it can be very hard to quit, or even to stop compulsively extending a binge. And heavy use of pills can cause crazy paranoid behavior like smoking or shooting can.

If you can draw a line and use it as super-caffeine a few times a semester, you'll probably be fine. It's an awfully easy line to slide over though. There are safer ways to have fun with drugs.

Two very important things to add: 1) be wary of mixing pot and alcohol. The one intensifies the other, and they end up being consumed together so regularly, you may not be thinking about just how badly it can fuck you up. Like the hangover the next day? Way WAY worse.

2) Know yourself and who you are as you make decisions about what you consume, and how much. Prone to anxiety? Dealing with depression? Attention deficit? On pills to deal with any or all of the above? Your limits are different. Read up and be aware of counter indications, and exercise judgment beyond what those around you are probably doing. It's a drag, but it's highly necessary and can save you a trip to the hospital, or a downward mental spiral that results in you flunking out of school.