Occasional self-medication isn’t inherently bad, but it shouldn’t be relied on at the expense of learning actual coping skills. Occasional recreational use is, in my opinion, not at all a bad thing--and that holds for things besides alcohol and pot. If you want to have a little fun every now and then, I see no reason why smoking a doobie with a friend once a week or so, or eating psylocybin mushrooms at a Phish show, can do any harm. And if you do it occasionally to get yourself out of your own head and reorganize your thoughts, that’s perfectly legitimate—I can personally vouch for the benefits of that. I don’t see why it should be viewed as any worse than having an occasional drink, and that is a definite cultural bias, as has already been pointed out. However, if you do it ALL THE TIME, that means you either have some serious problems that the drug alone cannot address, that you lack proper and reasonable coping skills, or that you’re just a pretty boring person; and, as with any substance, doing it to excess is a terrible idea. Even regular use, however, is not necessarily a road to addiction, perdition and despair; when that happens, there are ALMOST ALWAYS other factors involved—socioeconomic, mental health, family life, etc.—and, while it may certainly be compounding things (it usually does), it is silly to put all the blame on marijuana alone. (I can think of many high-functioning stoners that I know personally—I used to be one, myself.)
As for health benefits and risks—far too often, I think a lot of people (mostly those who enjoy drugs recreationally) jump on the fact that these drugs are being studied, but ignore whatever the actual results might be. And, as with anything in medicine, “preliminary results” means almost nothing. The fact is, there is no such thing as a panacea for mental or physical health, however much one sees it framed that way. As to whether marijuana can be responsible for lung cancer: I can’t imagine why it wouldn’t be; it has many more carcinogens than tobacco, and, while one usually smokes many more cigarettes in a day, I would be highly surprised if daily use didn’t have some adverse effect there. I would be interested to see people here link to some actual WELL-CONTROLLED and LONG-TERM studies. There is definitely a lower risk of dependency than with, say, alcohol, or heroine, but ANY substance that alters brain chemistry like that is not exactly risk-free.
I think some people in this thread on either side are coming down far too hard on this, and relying far too heavily on anecdote.
well, you should look at it differently. (And again, I haven't read other comments, if somebody have said something similar, sorry 
