Down with the Sickness
**Disclaimer from DM Wolfsfox: This article talks about phobias, mental health and things that may not be comfortable to every reader or person. The game Call of Cthulhu is a mythos horror game where player sanity is written on the character sheet and comes into play. As a Keeper it is important to make sure that your players are having fun and are comfortable with what is going on at the table.
The Game
In Call of Cthulhu there are lots of things in play when it comes to a player's sanity. Bouts of madness, episodes of mania and the true fear that phobias bring are no stranger for those who have seen the horror and experience the mythos. There are lots of resources that are available for keepers looking at the different options to play with player's sanity. Behind my Keeper screen I keep the Keeper Deck: The Phobia Deck and the the Call of Cthulhu Keeper Rulebook. Chapter Eight in the Keeper Rulebook is a section on Sanity.
Each character has a given amount of Sanity Points that are carefully tracked on the character sheet with every SAN roll needed to be made. When a player comes close to horrors or cosmic truth it challengers the investigator and a roll is made to see if they can push through the horror. With each loss of sanity points it changes the investigator and when the Sanity points go to zero the character is permanently insane.
At my tables I personally enjoy the moments where players have to make a sanity roll. Some players when they loose their sanity will automatically fall into roll play and decide for themselves what makes sense for their character. I have had an investigator at my table threaten other investigators with the shotgun they were holding after taking down a ghoul and couldn't handle the fact that they killed something. I have had investigators hallucinate dead love ones causing even more emotional trauma. Once I even had a player pull one of the cards that will be discussed below and had them freaking out because he was "watching" [hallucinating] that the other investigators were spontaneously combusting in front of them.
No matter what the sanity point total is when an investigator fails their sanity roll it causes an involuntary action such as jumping in fright, screaming or other actions as stated in page 154 of the Keeper Rulebook.
The rules as written for Call of Cthulhu 7E there are three types of levels that begins with a bout of madness in phase one, then underlying insanity with phase two and in the final phase is recovery. More on this can be found on page 155 of the Keeper Rulebook.
There are lots of ways to cause the sanity loss that brings players closer and closer to madness. When a person loses a fifth or more of their current sanity points in "one day"'s worth of game play they become insane. If a person's sanity ever goes down to zero they become permanently insane.
Phobias
There are lots of familiar phobias that can be found in the game. Some of these include claustrophobia, arachnophobia, acrophobia (heights) but there are so many more to explore. What I have written below is just a slim selection from the masses of mental anguish.
How about that homichlophobia? The Fear of fog (and humidity). Living in a state that gets some really humid summers and this would be a fear that would trap investigators in their houses. Make the fog ambience bring more than just setting the scene.
If you hate card tricks and magicians you may have rhabdophobia. Make your investigators quake and feel the dread of the Cthuhu Mythos. Sanity rolls required to not fall catatonic.
Eisoptrophic is a fear of mirrors. An unusual quick that goes beyond breaking mirrors bring bad luck. Do you see that person looking at you? Hope your investigators doesn't go to the local carnival or go by a mirror that is uncovered.
Bibliophobia makes all library rolls pointless as your investigator has a fear of books. A whole new meaning behind a hatred to read. Even seeing a book brings a level of discomfort. Hope your investigator never has to do research.
Ligyrophobia is when loud noises literally scare the life out of you. When exposed to loud noises it causes the investigator to have a phobic state of fight or fright along with hyperventilation, muscle spasms, dizzy and palpitations.
Manias
When an investigator at your table goes insane you can assign them a mania to be added to their investigator's character sheet. Instead of fears these are compulsions.
There are manias that are the extreme opposites of their equally named phobias (for example ligromania is where your investigator feels compulsed to do everything in extreme loudness where ligrophobia is the fear of loud noises). Some of the classics are kleptomania (stealing), mythomania (lies & exaggerations), and pyromania (burning).
One of the more strange manias is coloromania where your investigator has a fixated obsession with a specific color whether it is you need to have everything of that color or you specifically fear it.
Agathomania is a pathological kindness where your investigator will do anything kind to other people including the enemies. Investigators help those around them making things easier for mobsters and monsters.
Hysterics
When the world becomes to much and the insanity increases sometimes the investigators will act out of character.
Perhaps the bout of madness they feel is fleeing in panic, or they go into a fugue state where your investigator blacks out for 8 hrs of what could be a a vicious time where memories fleetingly return 1d10 hrs later. Amnesia is fun to play with where the keeper decides what happens when the memories go dark.
Other options include paranoia, or violence, or they start becoming compelled by their faith. Hysterics could be as easy as your investigator finds everything so funny, or terrifying enough to non stop screaming. The main focus of bouts of madness is the investigator character has mentally hit their limits and these actions are no longer things they would do in their right mind. Role play can add the stress level at the table and bring flavor to the adventure as bouts of madness change a person in seconds flat at the failed roll of a sanity check.
This article shows cards from Call of Cthulhu Phobia Deck created by Chaosium Inc. copy right 2016. It also has information from the Call of Cthulhu Keeper Rulebook also published by Chaosium Inc. published in October 2015.