Crazy for the Demon Lord

Shadow of the Demon Lord uses insanity to describe the effects of encountering the awful. When a character sees something that doesn’t belong in the world, witnesses an atrocity firsthand, or is subjected to something of profound wrongness, insanity is often the result. Like damage, insanity is measured as a number. You accumulate insanity, rather than reduce some other resource. The maximum insanity a character can accumulate is its Willpower score.
Gaining Insanity
When the GM decides or when the rules direct that a character is at risk of gaining insanity, the character must usually make a Willpower resistance roll. On a failure, the character gains 1 or more insanity and becomes frightened for a number of minutes equal to the character’s insanity total. Gaining insanity from some creature has additional effects such as with the hag. A creature that gains insanity from a hag also becomes compelled for a number of rounds equal to the character’s insanity total.
One way characters can rid themselves of insanity is to spend insanity to buy a quirk. Once each day, a player may ask for a quirk. If the GM agrees, the player reduces his or her insanity total by a variable number and acquires a roleplaying trait appropriate to the source of the insanity. For example, a character who recently gained insanity after encountering a bloody bone might have a fear of raw meat. Quirks can be phobias, addictions, nightmares, and a variety of other disorders acquired from great mental strain.
A character cannot gain more insanity than his or her Willpower score. When the insanity total reaches the limit, the character goes mad. The effects of madness are random and example forms of madness are included in a big, saucy table. Once the character recovers from going mad, the character removes insanity from his or her total.

Here’s an excerpt.

1 or lower         Death. Your heart stops and you die as a result.
2                       Catatonia. You fall prone and become defenseless. At the end of each hour, roll a d6. A 4 or higher ends the madness.
3                       Self-Mutilation. You must take the next turn you can and use your action to tear your eyes from your sockets. Unless prevented, you become blinded until your ruined eyes can be repaired—such as with the restoration Life spell. The madness passes at the end of the next minute.
4–5                   Stricken. You become stunned. At the end of each minute, roll a d6. A 5 or higher ends the madness.
6–7                   Sickened. You become violently sick, vomiting and defecating as a result. While sickened, you are dazed. At the end of each round, roll a d6. A 5 or higher ends the madness.
8–9                   Hallucinations. You believe vermin infest your body. While affected, you must take a fast turn each round and use your action to cut or claw yourself unless you are prevented from doing so. Each time you take this action, you take 1 damage. At the end of each round, roll a d6. A 5 or higher ends the madness.