Insanity Tables for Cthulhu over GURPS

Gene Michael Stover

created Saturday, 2022 January 1
updated Monday, 2022 January 3

This file is https://cybertiggyr.com/lwqyl.html.

What is this?

These are house rules for our group.
In a GURPS game that resembles Chaosium's Call of Cthulhu, we want insanity attacks frequently
The usual insanity tables in GURPS have lots of stunned.
All that stunning can leave a character inactive for a long time. (Even the GURPS Horror book mentions this.)
It's not so much that stunning could be lethal. The problem is that it's boring.
So here are some alternate rules about insanity.

Instability Tracker

Each character gets an Instability attribute.
Instability starts at 0. (That's good.)
Every failed fright check increases instability by one.
Every fright check passed decreases instability by one.
Fright check is 3d6 + instability.
“Quiet time” can decrease instability, maybe a point per hour. (Or make an IQ roll each hour, each time you succeed, you decrease instability by one point.).
Between adventures can reduce instability.

Insanity

Lasts for at least one turn (that's both in combat or out).
If you are in a situation where you are counting time, not turns, then say it lasts for at least a minute.
It ends when character succeeds in a Willpower test. Make the test at beginning of character's turn (or beginning of each minute).
If someone spends their turn to help you snap out of it by slapping you, shaking you, maybe a few other things (but probably requires physical contact), you can make another check to snap out of it then & there.

Table

Gamemaster rolls in secret & doesn't tell the afflicted character the result until the beginning of their next turn. And tells them in private, so they gotta act it out, let their teammates figure out what's up.

2d6	result
2	Lie to your teammates! If you you mislead the other players in a way that has in-game consequences, you reduce your Instability by one point! If you say something that's obviously bullshit, you do not reduce your Instability. Lasts until you pass your Willpower test at beginning of a turn. (You might need to tell many lies.)
3	Acquire a temporary mental disorder. You automatically recover after an hour of real-world time.
4	“Controlled” homocidal or suicidal mania. In combat, you can only do All-Out Attack against nearest opponent. Outside of combat, you start combat (shouting). You are not required to attack your friends, but you will attack strangers if there are no enemies nearby.
5	“Controlled” fit of screaming, laughing, or crying. You can keep the volume low if you want, so only someone within arm's length of you will hear it. You can't say anything useful. In combat, you can only do basic attacks, defend, or flee.
6	Uncontrollable eating desire. You eat something, even if the best you can do is lick the dust from the stones under your feet. But if there's something more obvious, you'll eat or drink that: rubbish on the floor, nearby carcass, grass, whatever. In game terms, you can't do anything useful during this time. And if you happen to eat something harmful, it could hurt you later. You don't need to (cannot) attack someone in the hopes of turning them into a corpse you can eat later.
7	Flee silently. You can shout if you want, but you can also keep silent.
8	Echolalia. You will repeat any vocal sounds that you hear, as best you can, at same volume level you hear it. In game terms, this means that if you are hiding & someone talks, you might blow your cover. Also, you cannot say anything useful to your teammates.
9	Hysterical screaming or laughing fit. In combat, you can make basic attacks, defenses, or flee. Outside of combat, you stand & scream. You can't cast spells, say anything useful to anyone, operate machinery, observe anythying, search, perceive. You just scream. And anyone with ears will hear you.
10	Flee screaming! In game terms, you are running at top speed in a random direction, making so much noise that everyone is aware of you.
11	Homocidal or suicidal mania. In combat, you can only do All-Out Attack against nearest opponent. Outside of combat, you start combat (shouting). If there are enemies nearby, you can chose to attack them, but if there are no enemies. you attack your friends. In other words, you attack someone.
12	Acquire a permanent mental disorder. (Permanent in that it won't go away without specific, in-game treatment.)

Notes

This is inspired by the insanity tables on page 83 in Chaosium's Call of Cthulhu Horror Roleplaying rules (6th edition).

Change Log

when	who	what
2022-01-01	gene	play
2022-01-03	gene	Sanity Tracker becomes Instability Tracker.

cybertiggyr.com