Mental health professionals appear to sometimes have a lack of ability to cope with the cycle of performativity and their clients knowing diagnostic criteria.
You can end up with more traits of a disorder if you know you have some traits of the disorder. But then mental health professionals don't think it's real because you broke the usual neuro-performative cycle. Sometimes people even make the ridiculous claim that there is nothing to treat. If a mental health professional claims this it just means they're too dumb to treat it.
There are also instances in which the disorder is performative, but not quite in the way you think.
On TikTok, tic disorders spread. People saw people with Tourette's, perhaps imitated a tic, and then got stuck like that. But they don't have Tourette's. They have FND.
Tourette's may not be able to spread. But tics themselves can.
This isn't to say everyone is vulnerable to such a thing. The brain has to be capable of being receptive to such a thing.
What I don't think people understand is that mental illness is a social construct and brains actually have a range of possible profiles that can change over time.
The cycle of performativity means that something deliberate can become accidental and vice versa.