Or to look at another way - what has been going on in the minds of these people -Miranda, Garner that they think themselves ill and then think themselves out of it?
This is why the model for this is a completely generic "life events". It can be literally anything. It can be a big thing. It can be a thing that happened to you many times, and this last one was just the last straw. Or whatever. It can be the sum of many small things. It can be no things at all, all subconsciously. It can just "be", just happen. Which makes it easy that literally anything can break it. The only way to move a mass of empty air is to replace it with another volume of empty air.
This is what led to the "chemical imbalance" model of depression, a psychosocial model which many people objected to because they were actually very happy at the time and had never faced significant hardship. There is no inconsistency with such a model that can't be fixed with a good old
Deus Ex Machina. This allows some random "bio" element to be glued at the right spot. No need to think any further. It all makes sense if you don't think about it.
The model requires no explanation and it can't ever explain anything. It just does what it needs to do, which is to convert something into another thing. All spontaneous in a completely black box process. Medicine's philosopher's stone, which having failed to find it, simply pretended that they did.
I posted a video in the "Bias in academic research" thread from a disgruntled physics academic who talks about the fundamental problems in theoretical physics, and how one of those is that with most of the falsifiable models having been falsified, all that's left is unfalsifiable models. They can't ever be proven definitely wrong. So they can be "worked on" indefinitely.
Like looping around the same area of space looking for a teapot orbiting the Sun. You can never be sure it's never in that specific area. So you can look at that specific area endlessly, since the teapot orbits around and it could be there now. Or now. Or now! Have you checked if it's there now? It could be there right now and you just missed it! Never stop staring at this one spot of space. Also you've already found evidence of that teapot, you just can't really show it because it's all complex and mysterious and so on. You just need a better picture than the blurry mass thing that could be the neck of some giant beast, or possibly a log. No way to know for sure. But you can say it for sure anyway, no one can prove otherwise.