zlacker

This isn't true for antidepressants, at least. Yes, each new generation has been oversold while it's in patent. But the efficacy of newer drugs has actually been very similar and the side effect profile generally better. Consequently, the NHS recommends SSRIs as first line treatment even though they have no conceivable profit-based reason for doing so:

https://www.nice.org.uk/guidance/cg90

The most significant clinical problem with antidepressant use is, as the NICE guidance makes clear, that different patients respond differently (or not at all) to different drugs, probably because depression is a constellation of conditions rather than a single disease. I can't speak to other mental health conditions (because I don't have them and don't follow the science at all carefully) but we're a long way from knowing all the causes of depression, let alone knowing how to treat it reliably in all patients.