Is this even meaningful? What you're saying is 'emotions are complex so feeling X might just be a more extreme version of Y even though it sometimes shares no properties with Y whatsoever' - doesn't that mean I can now say any experience is just an extreme version of any other?
Schizophrenia is really a lot like extreme happiness! You have any problem with that?
>On the contrary, I don't see why we need to put things into special categories in order to respect people's problems and properly judge their seriousness.
I didn't say put them in 'special categories' (most of the 'mainstream' attitude I experience is that I'm full of shit and should pull myself together, by the way), I said be careful and don't just speculate as if it were a folly in a public place like this, since you risk coming off like you're downplaying it. You can categorise however you like, but _back it up_ and have a little compassion. This isn't a programming language pissing match.
Saying severe depression is a more extreme sadness potentially implies you should do some lovely happy nice things to fix it like you can with milder sadness - much like the usual bullshit I hear about how if only I did more exercise it'd all be fixed and really you can fix it if you just put some effort in! Never mind that the lead PT of the biggest fitness brand in the UK jumped off a cliff, or that many people with seemingly great lives have committed suicide...
Saying something is just more of something else, implies that usual fixes apply, just you need to do more.
I'm not saying you think any of this, but that you need to tread carefully - these are actually I think (and experience) most people's views anyway, even if they don't want to say it, so both for depressives and those who might interact with them, you're potentially doing harm - is you waxing philosophical of more value than that potential harm?