Is being a Highly Sensitive Person (HSP) a thing?

[AtmosClock]

I have come across a few friends (mainly on social media) who identify as Highly Sensitive. Of those friends, their children are naturally also HSPs, and I've seen a few articles about how they tend to be smarter, kinder, more aware of social injustice, etc. However, most of their experiences sound very normal to me (needing me time, feeling sad watching a film, etc).

My natural inclination is to think this is a bit of a fad to make some people feel a bit better about themselves, but I do have an open-mind.

Is being HSP a real thing, is it diagnosable professionally, and what is it like? Or is it a fad?

I thought maybe this was me. I can be over-empathetic, have sensory-processing issues. Turns out I’m actually autistic. I do think there’s people out there who are sensitive. I also think there’s a lot of people who want to identify as ‘special’. This is an undiagnosed category so people can just identify and claim to be it.

I was thinking about this again today, wondering if some people's reptilian brain is stronger than their more evolved brain. That would look like someone being over sensitive to threat, having a strong gut reaction etc. I've read about it as an underlying cause of psycho somatic illnesses.