DMT is a drug which expands consciousness. In the Dune books, there's a drug which is called Spice which also expands consciousness. The funny thing is that the street name of DMT is Spice, so I was wondering if the two are related?
It seems unlikely.
During the early 1960s (when Dune was researched and written), N,N-Dimethyltryptamine had only recently been discovered in South America. Although some scientific research had occurred in the late 1950s, it is unlikely that Frank Herbert, then living in Florida would have had access to this relatively new drug.
The effects of Melange in the book Dune are dramatically different to the effects of N,N-Dimethyltryptamine. Notably, DMT's effects are short-lived and characterised by hallucinations of other-worldly presences rather than the "time trip" experienced by Melange users.
Finally, it's been described by Herbert's friend Paul Stamets (in his semi-biography Mycellum Running) that the key influence for Melange was in fact his passion for experimenting with hallucinatory mushrooms:
"Frank went on to tell me that much of the premise of Dune — the magic spice (spores) that allowed the bending of space (tripping), the giant worms (maggots digesting mushrooms), the eyes of the Freman (the cerulean blue of Psilocybe mushrooms), the mysticism of the female spiritual warriors, the Bene Gesserits (influenced by tales of Maria Sabina and the sacred mushroom cults of Mexico) — came from his perception of the fungal life cycle, and his imagination was stimulated through his experiences with the use of magic mushrooms."
the drugs themselves have no real relation to one another Spice or Melange is highly addictive, extend lifespan significantly and gives one precognitive abilities DMT may be addictive but the other effects are not present.
The term spice is a common one for fantastic drugs especially in a sci fi setting. Etymologically speaking its hard to say where the first usage came from but its probable someone heard it somewhere and decided to start calling their drug spice cause they thought it sounded cool.