No, just asking for proof of something. Why do you seem to have a problem with that?
I’m not sure what proof you expect here. It would all be contained in peoples’ PET scans, which would be confidential.
You deny that some people produce less serotonin than others? Because that’s basically what we’re discussing, and it’s widely proven. It even passes the common-sense test.
Here. 47,300 scholarly works on the subject. Take your pick.