I grew up in the heyday of the "Just Say No to Drugs" and "This is Your Brain on Drugs" public service campaigns, so my automatic knee-jerk response is, "Drugs are bad, bad, bad!!!"
However, I have to wonder if the identity of who uses drugs has changed over time, kind of like tattoos. It used to be that only the "wrong" people got tattoos, but now even my pastors have them. When I was growing up, drugs were always associated with the "wrong" crowd, but the more I talk to people, the more it seems that all too often, the "average drug user" is someone just trying to get by from day to day with less pain, whether mental or physical.
I've always worked in environments where some of the employees are expected to do constant, heavy lifting all day, and most suffer from chronic, constant back pain. Many take drugs in order to alleviate their pain. One person I talked to even said that he could take street drugs for a fraction of the price of prescription drugs, so he would take street drugs to relieve his back pain and then sell his prescription drugs to others for a huge profit every month. This wasn't some "lowlife scum of the earth", this was just a regular, hard-working guy trying to support his family. In situations like this, I feel torn, especially when it's said that some of these drugs can relieve pain for cancer patients, etc.
Sometimes we treat animals better than people. When animals are in chronic, constant pain, we put them down. But with people, God didn't give us that choice, and living in constant pain every single day is miserable.
I've also found that Christians have a very wide and varied view of this topic. I've met many Christians who felt things like weed are "natural" and can't be wrong because "God made them". They feel that these substances are just as legit as prescription drugs, it's just that the government regulates what's legal and what isn't. After all, as described above, many people today (often senior citizens) are selling their prescription drugs for profit, and sometimes just to get by (just as with street drugs.) This brings us to the question of what should even be considered an "acceptable" drug or not.
I once went out a few times with a guy who smoked weed everyday. We went to an amusement park one day that was in another state, and I offered to drive. To tell you the truth, I was so naive at the time, I didn't even think about it. When we got home, it dawned on me that he had taken a stash with him and I could only imagine the trouble I would have gotten into since he was carrying it in my car (at the time, it wasn't legal in ANY state.) Several years later I also had a boyfriend whom I'm pretty sure was using drugs, but again, I was just too naive to really think about it until after the fact. I realized how much trouble I could have gotten into just by association and I will NEVER put myself in this situation again, at least if I can help it.
Sometimes someone will ask me what I think of someone they're interested in and will add, "Oh, he just smokes a little weed," and my automatic mental reaction is, "A little weed? How about a little jail time!" I do have a lot of compassion for the people who smoke it as daily pain relief. However, I'm still not comfortable with being around any of it personally. I had friends in college who were experimental drug users but they didn't do it around me. I'd leave their houses before "the party" really got started.
I can only become so close with people who use what I consider to be illicit drugs, or are using drugs in an illicit way (I wouldn't be comfortable with someone selling their prescriptions, either.) I might be friends with them in public social situations (work, groups, etc.) but I wouldn't hang out with them much on a one-to-one basis. There's too many other factors involved with the culture that I wouldn't want to be a part of, not to mention risking being put into prison just because of being around the wrong things at the wrong time.