Does Diana Stanley gain sanity from doom tokens when the environment "Dream of a Sunken City" is in play?
Diana Stanley's unique ability:
Dark Insight - Any Phase: Gain 1 Sanity or 1 Stamina each time a doom token is added to the Ancient One's doom track
Dreams of a Sunken City Mythos card:
Mythos Ability: Investigators cannot gain Sanity except by receiving psychiatric care at Arkham Asylum (or from Carolyn Fern).