I think there are some cases where meditation can hurt rather than help. Although it is supposed to be good for anxiety and depression, there is a slight possibility it can make things worse, at least to start with...then of course if you don't stick with it because it isn't helping you are left in nowhere land. I also wonder if it would be helpful for psychotic disorders or anyone who is prone to hallucination or anything like that. I would say for the vast majority of the populace, however, it is definitely a good thing.

Another thing to be wary of is these "open your third eye" fast or "raise your kundalini now" type meditations. I think too many people are in a rush for everything, including their spiritual evolution and I have heard the road can get bumpy if you try and do too much too fast.