There are ways to conduct the research. Samples can be taken before, during and after and EEGs etc can be done. Trouble would be getting ethical approval and funding for it. Consent issues would be a nightmare legally (and, yes, I'd volunteer as well )

I have been in subspace, apparently. At least the Mistress who was working on me said she recognised the symptoms - can't say I noticed myself. But I was able, it seems, to take a lot more pain than normally I would. I'll know more when I actually watch the video. I didn't get subdrop, though...

I think one confusing aspect would be the similarity between subdrop and love - when you love someone it is the same feeling when they leave you.