Just be careful about the credibility of info you are reading , and how old it is. Some studies were done with T's aren't even certified, so the studies are bogus. It is important to go with someone who is trained level 2 is the best. They should have a certificate that proves they have been trained.
I have seen it do wonders with others and me personally. I plan on being trained when I am a T, because it is very effective in treating PTSD.
It even does things that enhances athletes and musicians performance. Most of the negative studied I have studied, were very old were the procedure wasn't performed correctly by qualified technicians. There are also T's out there who think they know how to do it because they read Shapiro's book, well you have to have the training to get the best results, so check to make sure they are certified to do it.
I even use the techniques on myself to calm myself when feeling nervous before a test or music performance.
I know it sounds like voodoo, that is what I thought, I am one of the most skeptically people around, but it works well for a lot of people and it worth trying if you can get some relief from PTSD.
T' s who have had to training know just how well it works because they have had it done to themselves. My prof. who is a T thought it was horse crap, until he went into the training and had it done on himself about a early memory. It it very powerful and needs to be done by someone qualified to do it.
There is a huge empirical study right now that is being conducted that we hope to hear the result in the coming year. They are even using brain scans that show the distress is so much less after a EMDR session. Now why it doesn't work for everyone (nothing does), there is a huge success rate if done by someone trained.