Hello Pandora,
I've gone through quite a bit of EMDR. About 13 years ago a therapist suggested it. I was worried about doing a "short cut" that wouldn't really be real, but he reassured me it was not, so I agreed to try it. My symptoms and distress got quite a bit worse for several weeks (I was really disocciative, I cried and slept a LOT, and my particular coping/distress symptoms worsened -- cutting and bulimia), but then suddenly it seemed to shift and start getting better. I needed a lot of extra support during the rought time -- counseling 2x a week, and a support group that met 2x a week. I don't remember how long it was, but it seems like it was several months of it. I actually didn't cut for 13 years (only recently backslid with that when I took a pretty severe header, which prompted me to go searching for support, which is how I found you guys).
I felt like it cleared a lot out in some ways, but when I tried it again a few years ago, to do more work, it wasn't effective at all - but maybe I'd gone as far as I could with that tool. Being very emotionally numb, it really helped me get to feelings. I have a friend, an incest survivor, who tried EMDR and it did nothing at all (although, she did try the tool - not sure of the official name - where she would tell the story over and over and over until it didn't have as much of an impact, emotionally, reliving it anymore and she felt like that one helped her a lot).
HTH,
Dylan