In mental illness there's actually a long and unfortunate history of people with problems being vulnerable to suggestion. People with mood disorders and anxiety will accept spiritual explanations for their problems. People with mental disorders like autism are even worse, because they're functional but may not do as well with evaluating emotions and their relative states.
Dissociative Identity Disorder, for example, was barely even a recorded thing until they started making movies about it, after which it exploded for a few years. You saw a lot of people saying they had alternate personalities, using it as an excuse to misbehave, usually. Especially in mental wards, where a doctor would tell their patient they had it, and then the patient would accept that and start acting out the symptoms.
It's a pretty real possibility this is why we've seen an explosion of the transgender stuff this generation. Because while people actually are sometimes born with physically ambiguous gender and it could be presumed to occur mentally too, it was extraordinarily rare before Twitter got a hold of it. That's also why the official term is "gender dysphoria", and not "transgender", because until the political movement I don't know if transitioning was legitimately considered a treatment. More like it was a rare problem psychiatrists never had tools to solve or properly evaluate.