I remember reading somewhere (does anyone remember where?) that while there's little evidence for one school of psychological or psychiatric therapy over another, there is strong evidence that spending a lot of time with an intelligent, sympathetic listener is good for you.
Me too. I've also read that teenage girls are as effective as professionally trained therapists... and even that you might not need a human listener at all to get the benefits; just keeping a diary helps.
http://lesswrong.com/lw/2j/schools_proliferating_without_evidence/ and http://lesswrong.com/lw/94t/meta_analysis_of_writing_therapy/ seem relevant.
If you want more detailed refs including the claim that the particular school matters much less than the quality of the therapist (with an honorable exception for CBT), http://counsellingbooks.com/bibliography/theory-and-research/general-and-comparative.html#LambertBergin_1994 http://counsellingbooks.com/bibliography/theory-and-research/general-and-comparative.html#BeutlerEtAl_1994 are relevant.
A piece I saw that Benjamin Todd adapted from THINK's module on charity assessment. Some of you may recall the network's recent launch.
cipergoth said that it should be emphasised that this isn't a trick question where the answer is they all worked or none did.
I thought Round 2 would have no effect and expected Round #5 to have no effect not a negative one, I got 6 out of 8 correct. How well did you do?
I recommend checking out the links and references. Gwern's comment there was also interesting.