Yes, I remember learning about this issue with psychiatric medications and being similarly dismayed.
There is a sub-field called Computational Psychiatry [1] trying to do better. And interestingly, a person could argue that randomized controlled trials for medicine are only really necessary because we don't have good enough theory and/or good enough measurement devices. If we did, we could reliably predict the effects of a medication without the trial.
i.e. "We don't quite know how it works... but statistically we think it will help, with these side-effects.. good luck" <gasp>