A recent New York Times article lays it out:
Fully 1 in 5 Americans take at least one psychiatric medication. Yet when it comes to mental health, we are facing a crisis in drug innovation. . . . Even though 25 percent of Americans suffer from a diagnosable mental illness in any year, there are few signs of innovation from the major drug makers.
The author has no understanding of the stagnation, yet is opinionated:
The simple answer [to what is causing the stagnation] is that we don’t yet understand the fundamental cause of most psychiatric disorders [what does "fundamental cause" mean? -- Seth], in part because the brain is uniquely difficult to study; you can’t just biopsy the brain and analyze it. That is why scientists have had great trouble identifying new targets for psychiatric drugs.
The great increase in depression has an environmental cause. Meaning that depressed brains (aside from the effects of depression) are the same as non-depressed brains. Someone who knows that would not talk about biopsying the brain.
You come to a room with a door. If you don’t know how a door works, you are going to do a lot of damage getting inside. That is modern psychiatry. I described a new explanation for depression in this article (see Example 2).
Thanks to Alex Chernavsky.