I don't know if this has already been posted. But I found this paper from 2007 very interesting (see attachment).
Seems 5-MeO-DMT (as well as other psychoactives) is quite a serotonin reuptake inhibitor. Didn't know that before.
I claim not that this is the truth. As this is just what got manifested into my mind at the current position in time on this physical plane. So please feel not offended by anything I say.