I think this post is interesting... I'm a fourth year student, and I can't honestly say that there were not times in med school where I wished that I could be doing something - anything else. One day last year, I stood at my apartment window and watched the mailman put mail in the boxes. And I was so jealous. What a nice life - to serve such an important function in people's lives without taking on the burden of actually feeling responsible for those people's lives.
But those days are relatively rare. For me anyway. I love what I'm doing. I am so excited to start my intern year. (Terrified, but also excited.) What it all boils down to for me is that I cannot imagine myself doing anything else.
Depression is terribly common in med school, unfortunately it is not talked about a lot.
This article from NEJM has some interesting facts about depression in medical school.
I think the best thing you can do for yourself in school is to NOT study all the time, and to NOT get drunk all the time. You need to surround yourself with supportive people - med students and 'normals.' If you make a conscious effort to have fun and to laugh every day, it is harder to become cynical. Not impossible, but harder.
Have I been depressed? Sure. Have I changed unalterably since undergrad? Definitely (but that would have happened no matter what I was doing) Would I do it all again? Absolutely.
Good luck to all of you preparing to begin.