The brain is a black box of complexity. Until we completely understand what's going on we don't even know if we're treating something that is even fixable. It's like adding random voltages to pins on a motherboard to try to fix a software bug.
Deep brain stimulation for Parkinson's is pretty incredible [1] and transcranial magnetic stimulation for depression is effective [2]. The open label studies on DBS for depression were promising, so it was perfectly reasonably to try it out in a randomized controlled trial.
DBS for Parkinson's (and dystonia and essential tremor) work reliably well, and the complication rates are considered acceptable. However, in terms of understanding the mechanisms of how they work on the brain, I would very much characterize it as a black box. So much so that if you look at the different ways different medical centers and practitioners program the devices, it's clear we don't know how it works; just that it does (and extremely effectively) once you fiddle around with the settings long enough.
I don't think anyone doubts the value of completely understanding what's going in the brain, but it's clear this is an insanely difficult task. It's incredibly difficult reverse engineering something as complex as the brain when we have little understanding of its capabilities and limitations unlike a digital computer. Until then, I don't see the problem with using various therapies to attempt to cure conditions. I definitely don't see the value in asking people who are suffering to wait until a seemingly unsurmountable task is completed.
Of course. Not all disorders can be treated with the blunt hacks we currently use though. I think depression is one of those things that can't be understood until we reverse engineer the brain.
