By “disruptive” I mean the mechanic breaks the immersion at a particular time. It affects the pacing of the fiction at hand, the immersion.

As a Handler (GM) in Delta Green games, during play I think SAN checks are often great to help build tension. They’re great during “Home” vignettes, as they kind of “ground” the little bit of fiction back into the advancement mechanics for Delta Green agents. They’re great during the investigative phase of a scenario – the slow burn period, where the Agents are finding out creepy stuff, and the SAN roll is like a validation they’re on the “right track”.

I do feel they are detracting from the atmosphere, when the proverbial shit hits the fan and the Agents are doing and witnessing all sorts of crazy stuff in rapid succession.

It feels like they’re breaking the “flow”, breaking the mood of the game right when it’s most important. Violence, Helplessness, and the Unnatural SAN based checks can come pretty fast.

By contrast, the D&D retroclone Lamentations of the Flame Princess deliberately eschews any sanity mechanic, even though it’s embedded firmly in the horror space. In the grindhouse edition of the LotFP Referee Book, Raggi writes:

In game terms, particularly horrifying or bizarre happenings or circumstances can trigger a Loyalty/Morale roll for NPCs in order to continue on/not run away. But Referees should refrain from imposing any sort of fear or sanity rules upon Player Charaters. Before long they will be acting in ways that the locals will consider insane anyway (professional adventurers do not act like normal civilized folks!), and it is but a cheap effect to try to simulate fear by rolling a die and saying, “You’re scared stiff!”

How about you? Do you sometimes find the mechanics of SAN (including projecting onto bonds etc to avoid temporary insanity) slow things down right at the most crucial moment of storytelling?

Let me know your thoughts.