Sanity, Trauma & Insanity System
Source: Call of Cthulhu 7th Edition Investigator’s Handbook
7e Official
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Rule Summary
Complete mechanics for Sanity loss, Involuntary Actions, Temporary, Indefinite, and Permanent Insanity.
Quick Reference Check:
5+ SAN in 1 turn + INT check passed -> Bout of Madness (1d10 rnds/hrs). 1/5 SAN in 1 day -> Indefinite Insanity. 0 SAN -> Permanent Insanity.
### The Sanity Check
When an investigator encounters cosmic horrors, grisly violence, or eldritch truths:
1. Roll 1d100 against current **Sanity (SAN)**.
2. If successful: lose minimal or 0 Sanity (e.g. 0/1d6 -> lose 0).
3. If failed: lose full Sanity expression (e.g. 0/1d6 -> lose 1d6).
### Involuntary Action
On any Sanity loss, the investigator suffers an immediate involuntary gasp, shriek, or flinch, potentially dropping an item or giving away their position.
### Forms of Insanity
- **Temporary Insanity**: Triggered if an investigator loses **5 or more Sanity points in a single round/incident**.
- The Keeper calls for an **Idea (INT) Roll**:
- If **passed**: the character fully comprehends the horror and immediately suffers a **Bout of Madness** lasting 1d10 rounds (in combat) or 1d10 hours.
- If **failed**: the character represses the realization and avoids madness.
- **Indefinite Insanity**: Triggered if an investigator loses **1/5th of their current Sanity in a single in-game day**.
- The investigator develops an ongoing underlying mental illness (phobias, paranoia, hallucinations) requiring institutional care or psychotherapy.
- **Permanent Insanity**: When Sanity reaches **0**, the investigator’s mind is permanently shattered. The character becomes an NPC under the Keeper’s control.