Friday, April 19, 2013

A Sanity Mechanic for D&D Type Gaming

The other day I looked at the role of the Sanity system in Call of Cthulhu, and how it creates another mechanical stress on the players and one that helps enforce the horror genre.  How would it work in something like D&D?

First - let's be clear on the goal.  In a horror-soaked D&D game, monsters are rare and otherworldly.  The experience of the supernatural is not commonplace - they represent a disturbance to the status quo and a violation of the natural order (from a human perspective).  A system that attempts to model the mental effects of horror implies that even hardened soldiers could be unnerved by direct exposure to the supernatural that defy categorization or understanding.  A mechanic would be put in place to attack the characters from an alternate angle and put pressure on the players as they face down supernatural threats.

In general, I prefer "less is more" and don’t like adding sub-systems so  I'd like Sanity mechanics to be simple, familiar, or both.

My first thought is something like this:  all characters have a permanent starting Sanity value equal to their Wisdom; from that point on, Sanity and Wisdom are not correlated.  Temporary Sanity goes up and down over the course of an adventure, but permanent Sanity rarely decreases and represents a hard cap.  There are some ways to heal temporary Sanity during an adventure, and lost temporary Sanity usually recovers completely between adventures.

Whenever a character is subjected to a horror, there's a chance their temporary Sanity decreases; the DM rolls a d20 against the characters current Sanity score (like an armor class), and if the roll meets or exceeds the score, the character loses some temporary Sanity.  (Conversely, if players prefer to roll, they're always trying to get under their temporary Sanity and 'miss' their Sanity).

Here's are some sample Sanity losses.  The amount is rolled randomly similar to weapon damage:

  • Seeing a monster at a distance, witnessing a mundane killing or a fresh corpse - 1-2 points.
  • Seeing a monster up close, finding a grisly murder scene, or experiencing unnatural omens or haunting effects - 1-4 points.
  • Attacked by a supernatural threat or seeing hundreds of corpses - 1-6 points.
  • Attacked by an overwhelming threat, like a horde of monsters or a giant thing; seeing the corpse of a loved one or friend; witnessing a supernatural killing - 1-8 points.
  • Seeing a good friend gruesomely killed by a monster - 1-10 points

Cumulative losses within a single encounter caps at the maximum for the worst loss.  If the characters are attacked by a supernatural threat (loss 1-6) and one of the party members is gruesomely killed (1-10 loss), the maximum loss for both events is 10.

Furthermore, extremely weird and otherworldly monsters would have a kicker - seeing something like Great Cthulhu might add 1-6 points of loss to the roll (seeing Great Cthulhu  rise out of the harbor and scoop up a handful of sailors and toss them back like popcorn would cause potential 1-8 and 1-6 points altogether).  Really outrĂ© monsters like the Outer Gods or Great Old Ones may always strip a point of permanent sanity.  I haven't decided if there should be a minimum loss associated with certain encounters, even if the Sanity misses.  Since we’re treating it more like Sanity attacks and damage, it might be good to stay away from "auto damage".

Once a character gets to zero temporary Sanity, they receive a -2 to all of their rolls and saving throws.  Once a character gets below -5 temporary Sanity, they're in deep shock and lose a point of permanent Sanity - an are they unable to function?  Do they gain a phobia or mental derangement?  I don't know yet - I need to see how other games have handled similar things and then run the ideas through some paces at a home game  (For now I'd treat "deep shock" as a Fear effect).  I'd also suggest a saving throw versus Death to avoid the loss of permanent Sanity.  At some point I'd expect a character might go permanently mad (at permanent Sanity = 0).

Anytime an NPC retainer or henchman loses half or more of their current Sanity, they need to make a morale or loyalty check.

Xameck the Mage and his small crew of mercenaries (Bart the Fighter, the priest Montjoy, and a retainer, Squire Deegan) are hired by the Burgomeister to discover the source of the grave robberies in the lonely cemetery beyond the village.  Climbing atop the Sarkhov Mausoleum, the group huddles down for an overnight vigil.  A village goodwife, recently deceased, was interred earlier in the day, and the lookout is spying on her fresh grave across the moonlit ghostyard.

A shambling, lurching figure emerges from the mists down below, startling Squire Deegan (make a check due to Seeing a Monster at a Distance).  Raising the alarm, the characters get to their feet and prepare missiles, but the monster lurches off into the darkness, tearing up clumps of earth with its hooves.  Since these guys are adventurers, they quickly climb down and begin to follow the monster's tracks.

The monster's path leads to an opened mausoleum, and the characters take a moment to light torches before entering the black interior.  There's only a large sarcophagus with a skewed slab for a lid within the decorative chamber.  Fearing an unholy terror, Montjoy waits at the end of the sarcophagus with a vial of holy water, while the two fighters get on either end of the slab and slide it open.

With a speed belying its ungainly size, the monster springs out of the depression and slashes Montjoy down the front of his chest with iron-hard claws.  As a 1st level cleric, Montjoy doesn't have too many hit points, and the other characters watch him drop to his knees, gurgling on his own blood before he dies.  While everyone in the group makes Sanity checks and prepares to draw weapons, the monster (in this case, a Lovecraft-style ghoul) barrels down a set of narrow stairs beneath the sarcophagus, and into a subterranean realm.

At this point, the characters have been threatened by a 1-2 Sanity loss (seeing the monster), a 1-6 point loss (attacked by the monster) and a potential 1-10 loss (seeing a friend killed right in front of them by the monster).  The cumulative maximum is still 10 points because these would all count as a single encounter.  It's possible some characters with low Sanity scores are "shaken", taking a -2 to rolls, and Squire Deegan might need a morale check before being willing to enter the ghoul's realm.

Obviously, we need to try the rules on and refine the approach, but just reflecting on the sample encounter, I can see that adding any kind of Sanity mechanic changes the complexion of even a "mundane" supernatural encounter into something different and makes each encounter more impactful.  I didn't spend much time with the Ravenloft 2E rules back in the day, and I've been thinking of checking those out as well to see what the mothership was doing to support horror-flavored D&D back in the 90's.  Anyone familar with the 2E Ravenloft setting?  (Someone pointed out Crypts & Things has a Sanity mechanic too - I'll have to check it out and see how it's implemented).

In the interests of carousing rules and soaking loose cash, the primary way to recover lost Sanity is to spend some money in between adventures - each day of spending 100gp (per character level) recovers 1-6 temporary Sanity points.  This money could be spent on any appropriate activity stipulated by the player as something relaxing or important to the character, but it can't provide other material benefits.  Examples include carousing, tithing to the church, research, or training.

Once per day while adventuring, the party leader can give a rousing speech to each character.  If the leader succeeds on a reaction roll (rolling a 9-12 on a roll of 2d6, modified by Charisma) the characters are inspired and gain 1-6 Sanity back.  Consider it a once-per-night pep talk or morale boost.

I'd have to go back through the clerical magic system and identify appropriate spells that should interact with Sanity hit points and damage; spells like Fear may cause Sanity damage in addition to their other effects, whereas Remove Fear could recover Sanity damage similar to a Cure Light Wounds.  Maybe high level spells like Restoration can restore permanent Sanity points.


  1. I did a Sanity mechanic a while back. I should see if I can dig it up at all.

  2. You might consider making high wisdom a penalty rather than a strength. A character with high wi sdom ought to be able to more fully comprehend the true implication of the unnatural horror he faces!

    1. Me, I'd make high intelligence the penalty. Wisdom, then, is strength of character, allowing the character to weather such shocking revelations, while intelligence is the key to understanding such horrors and one's ultimate insignificance in the grand scheme of things. So, maybe a penalty to the Wis check equal to the Int bonus on the standard bonus chart? Low Int characters then become more resilient, as they don't really understand what they are seeing.

  3. I'm reading from work and therefore unable to offer any real insight right now, but I like faoladh's idea above.
    If you want some random insanities to playtest with I've got some here:
    Just search for "Insanity" and you'll find the table.

  4. from real world experience... PTSD in combat veterans is more frequent in soldiers with low education, low intelligence, smokers (low wisdom?) and low rank . .. Obviously PTSD is more common in frequent with SMs with multiple and prolonged deployments.

    Soldiers with severe head trauma, specifically, damage to the amygdala are LESS likely to experience PTSD than those soldiers with minor traumatic brain injury.

    Do not challenge me on these FACTs, I work for DVBIC.

    1. "Soldiers with severe head trauma, specifically, damage to the amygdala are LESS likely to experience PTSD..."

      Could you get specific on the exact effects of damage to the amygdala?

      Also worth noting, it is sensible that war-PTSD and Cthulhu-PTSD are different. Although high inteligence, education etc. might be useful for fighting traumatic experiences, in our case it also makes experiences more traumatic. A fair solution would be that intelligence both increases max sanity and the odds of losing sanity.

  5. Have you looked at Call of Cthulhu d20? They have a Sanity system at the back of the book as an optional rule for D&D games (although geared for 3.x style D&D)

  6. There is an option for this in the 3rd E. Unearthed Arcana. They take WIS and multiply it by 5. Sanity checks are a d100 under the result. Rolling more than that makes a character loose sanity. There's more to that (as an optional rule, casting could make you loose sanity, for example), but it's really a complete subsystem of optional rules. One of the more interesting ideas to take into consideration the fact that this is fantasy, was to allow a character to ignore any sanity loss as high as his level (or lower).

    Tried to use this with my group (using the Rules Cyclopedia), but one of the players stated that we played D&D. They were heroes when confronting monsters and they shouldn't turn into quivering fools fighting them (mostly because of bad luck: the first trial for this subsystem resulted in a critical failure and a dwarf pissing himself, unable to fight the undead they encountered...). I left it at that. Still like the concept, though...

  7. I know this isn't everyone's taste, but given the periodic reminders that hit points aren't actual damage, but an abstracted wearing down of endurance, I've been considering having the things do triple duty:
    * Worn down from combat: hit point loss.
    * Cast a spell: hit point loss.
    * Unsettling horrors: hit point loss.

    Refresh daily though assuming adequate rest and nourishment.

  8. I used Call of Cthulu's sanity rules, transported whole, in AD&D just while running Tegel Manor. It added a lot to make the scenario stand out.

  9. This blog post brilliantly illustrates why a sanity mechanic isn't appropriate for D&D. Some particularly fearsome and weird entities might give off a fear aura (rooted in magic), but rolling dice to see how scared the PCs are of undead and bizarre beasts isn't the answer. D&D is a fantasy roleplaying game, after all.

    Instead, I would encourage DMs to describe monsters in such a way that makes the player afraid. That's the true moment of horror.


    1. Note that Sanity and fear, although possibly linked, are NOT the same. If sanity loss causes fear, that's one thing. If fear causes sanity loss, that's another. But from a Lovecraftian viewpoint, although many things can cause both, sanity loss is not about being afraid, it's about the brain saying "Screw this crap, I'm not being paid enough for this." and going on indefinite vacation because it perceived something it cannot (or should not) comprehend.

      Is Cthulhu scary? Sure. Is that your bigger problem? No way. Example given, Dreams in the Witch House: the guy is slowly driven over the edge because of exposure to multidimensional space. The 4th dimension isn't really scary. It is just horridly weird, and you get the same result a low-cost calculator gives when you multiply the maximum number it can handle with itself.

  10. The thing I don't like about most Sanity systems is that they function too much like hit points: that is, you don't start to worry until they start to run low. They're another abstract resource that can be depleted.

    I've been pondering a sanity system where seeing crazy stuff gives you a gradually increasing chance of breakdowns.