I completed this study at BU. They are testing D-Cycloserine for its efficacy in increasing people's response to therapy. As you said, it helps unlearn social behaviors and thoughts. The therapy during the study was working for me, but my success turned around for a number of unrelated issues. I do not know if I received the placebo or the actual D-Cycloserine, so I can't speak to it's effectiveness.
Do you know when the study is supposed to be released?