Chemjobber and Vinylogous are having an interesting conversation about mental health in chemistry graduate programs, much of which is directly applicable to my own experiences. The comments show I'm certainly not alone in having a neglectful advisor who then occasionally smothers me with attention. In the comments, there's also a lot of talk of the need for institutional support systems.
I've found that far and away, the most important thing I can do for my mental health is this: talk to people who aren't in grad school.
Talking to other grad students tends to devolve into pissing matches of who has the worst advisor (with smug thumb twiddling from the few with good advisors). While it can be cathartic on occasion, it gets very dark and depressing to spend that much time focusing on the negative parts of grad school. It's also *really* depressing when other people are complaining about something, and you're just thinking "Wow! They get feedback! I wish I got feedback!".
Frankly, I'm in a much better place emotionally than I was at this time last year. Nothing has really changed about my advisor or the stresses in my working environment. We finally got the first paper out, but reviewer data killed the next three I'd written, so that's a wash.
Now, I have a much better group of friends who have nothing whatsoever to do with grad school. I have a weekly craft night (aka Stitch and Bitch night), and belly dance classes. It really helps me put grad school back in perspective. I have fairly flexible hours, in that I'm not forced to work third-shift. As a computationalist, I can work remotely if I want to (and don't need certain software licenses...) It's also a nice ego boost to be considered smart again, instead of average at best.
I still have stress-triggers that can turn me into a wreck, such as having multiple people ask me "So when are you graduating?" in too short of a time frame, and thinking about how slowly my advisor reads is a good way to get me in a destructive mood. But guess what? These topics come up rather less often when you're not talking about school.
Of course, there are other coping mechanism, like finding other mentors for feedback, and solo hobbies, and whatnot, but sometimes, you just need to escape the echo chamber.