An example would be autism. It had the same kind of "sudden growth" back in the 1980s when diagnosis became more accepted and practiced. But there didnt suddenly exist more autistic people than before. Just more people who got it diagnosed and help from their doctors.
Imagine if the catholic church approved stigmata as a way of showing one's devotion. I suspect the number of people suddenly getting scars on their hands would sky rocket. Doubt any of them would actually be channeling Jesus.
There are very few conditions that are real and they have easily detectable and unambiguous physical signs, e.g. epilepsy.
The rest of them are ways for people to show distress, either positive or negative. The positive side would be stigmata 'look at me and how holy I am' the negative would be witches 'look at me and how unholy I am.
Transgenderism moved from the negative distress to the positive distress pile in less than 5 years last decade and people are having a hell of a time dealing with it.
The 'acceptance' of deviancy isn't helping, it's just pushing people to become more extreme in what they do to show their dislike of current society.