I think what the parent was trying to say was that "antibiotic" describes the drugs' method of action, while "antidepressant" describes the drugs' intended affe

I think what the parent was trying to say was that "antibiotic" describes the drugs' method of action, while "antidepressant" describes the drugs' intended affect. > due to the ill-understood nature of the brain, I think this is exactly the problem. We have a bunch of drugs that seem to work, and we think we know how and why they work, but we're not able to directly measure the problem in those terms. If someone has a bacterial infection, we can culture it and prescribe the correct antibiotic. If someone has a mental health condition, we almost always have to consider the way that it's presenting and make an educated guess as to which drug is going to be effective. It's not at all uncommon for that first guess to be incorrect, which leads to either iteration or a "cascade" depending on the practitioner.