Patents last 20 years.
If any company, today, cured major depression with a drug, it would be making essentially monopoly profits for at least five, while analogs were found, at at most until 2036.
I come from a cognitive/social psychology background; it is mostly social psychology that has a replication crisis. Double-blind drug trials, even with psychiatric drugs, are usually fairly well done. (That doesn't mean the theory behind these drugs is necessarily sound, and in fact we're learning that a large class of drugs, SSRIs, may only provide a primary effect along a previously though auxiliary axis).
It seems hard to argue that any alternative medicine field is as productive or as effective, empirically speaking, as the drug companies. They have huge incentive to win big and they go for it all the time. In the US they can sway things a little with ads, but only after they get past our admittedly corrupt regulatory gatekeepers, and only in that market. A cure for major depression alone would be 7-20 years of guaranteed monopoly profits. There is not a drug company in the world that would keep pressing SSRIs if that sort of treatment was available. The brand loyalty alone would be well worth it.
This isn't to argue against anything, really, except that psychiatric drug manufacturers have incentive not to produce cures. They assuredly do.