It is the Holy Grail of psychopharmacology to divine the proper class of psychoactive drug for each patient ahead of time or even type of therapy drug-based or not. Lots of work across different disciplines going on toward that goal.
Even without a perfect means, even a rough approximation might help doctors give better care to patients. I don’t think bio-markers will tell the whole story. The compleat physician has a spiritual and psychological side. Sometimes, to put it bluntly, the best cure is Jesus, ministered in a custom manner to a patient.
It is maddening that there is no rhyme or reason behind which antidepressant works for who, if any. It almost feels like they are all placebo. You’ll have someone try one after another, and then get a new boyfriend, and the random drug they were on at the time is “the one that fixed everything”. I need black and white, cause and effect type evidence. Until then, I have no recommendation. Try the cheap one.