This is one thing I like about my doctor--he regularly admits he really doesn't know how different things work. I assume I have a chemical imbalance because drugs mostly correct my problems, but it's true that we don't know the mechanism behind this. I've always personally believed that there may be multiple different causes for what we call "bipolar disorder". We still are forced to diagnose by symptoms alone, which is notoriously inaccurate for pinpointing other problems in medicine. I hope research will someday actually identify the cause or causes of bipolar disorder and then maybe there can be truly valid and logical treatments. For now we're all shooting in the dark to some degree.