Without the threatening factors of illegality and social castigation poised like the Sword of Damocles, one can see specifically which drugs have precisely what effects on people at a very basic and honest level. Based on these observations, it makes no sense that alcohol is legal while marijuana is not. I've used just about every drug there is at least once and some many times. I drink regularly, smoke pot regularly and use coke, meth, ecstasy, acid and mushrooms occasionally. I've never been in any sort of legal trouble over drugs and they've never caused me problems in my personal life.
Prison is a chronically stressful environment where almost constant tension and turmoil reign.
I am basically a happy person. In spite of that there is always some degree of stress present. Not enough to make me miserable or even unhappy but enough to manifest its presence. When I was in Federal prison, marijuana was medicine to me. I smoked it almost every day.