Definitely more Dune. Withdrawal can, very often, lead to death. It doesn't give you good old blue eyes or leave you forever stranded, but it's a lot less soma and a lot more the spice is with you.

Minus the mind boosting effects.

Or giant sand worms.

Verstatsi is well known to all Exiles, if what it does in particular may or may not be. ALl members of the United Earth, as far as anyone in Exsilium knows, are on verstatsi. Likely they've seen or known at least one person who has detoxed from verstatsi. Also likely they know someone or have at some point tried experimenting personally, some to be curious, others to figure out what it is that helps make people be okay injecting this stuff on a daily basis.

As for the app sample, that should be fine, as long as there's enough introspection interspersed with the rest to get a sense of character voice and thought process.