Sanity

I'm reminded of Earthdawn and Horrors (wish there were better mechanics there for similar sanity).

From reading what you have - you seem to have established 3 knobs in your layout. 
 * Temporary sanity loss
 * Permanent sanity loss
 * Mental debilities (different insanities). 

I imagine that temporary sanity loss is recoverable (seeing something horrific you break and run in panic, and hide under a bush for several days while you pull yourself together).  Permanent sanity loss is the sort of thing you give up to be able to witness something or wield something without breaking (that little piece of your mind, walled off like a secret garden, where the memory hides), or you see something so incomprehensible your mind cannot hold together after.  And mental debilities ... ... ... how about them gods?

But adam is right.  Cthulu can be that awful (or is it awesome?).  Sometimes when you see something there's no coming back from that.

I find it interesting that there is a level 9 cleric spell that COULD deal with such effects of trauma (Recovery) ...

When you find some peace and quiet to search your soul, each other player will ask you about a time in your life, which you must answer honestly - regain all but one of the sanity you lost.

You could use sanity as a counter for over-the-top or humanoid-on-humanoid violence, too.  It would dramatically recolor your setting; it's something that could alter the feel of the game pretty significantly.

When you commit violence against a sentient being, spend 1 sanity.

That's remarkable.  Just this morning on the drive to work, I was thinking of drifting Apocalypse World with almost that exact idea.  I was thinking of a 'humanity' countdown clock that would suffer when you killed folks.

Unless you play a fairy, then your humanity goes up whenever you kill people.  Eventually you turn into one of them!

Straight from Mr. Harper :)
When you steel yourself against the assualt on your SANity roll+SAN. On a 10+ you’re fine. On a 7-9, you’re shaken. Choose one:
*Flee, freeze in shock, scream in terror, beg for mercy, or collapse in fear.
*Take -1 ongoing until you are safe.
*Suffer 1 SAN loss (visions of madness) but you’re free to act.
On a Miss you break. Flee, freeze in shock, scream in terror, beg for mercy, or collapse in fear and also suffer 1 SAN loss (nightmares) as established.

Yup, that's what I was thinking: permanent sanity loss is the big bad thing beyond your initial reactions of shock and horror and flipping out. Oh, sure, you can keep it together even when you would flip out, but that means inviting long-term problems.

Exactly :)

How about adding as an option for a 7-9 on Cast a Spell:
• you lose N sanity

And the same for a 7-9 on Last Breath.

Uh?

Sanity loss as a spell option is good.  I would say it could replace the "you forget the spell" option and I'd reword the "you draw attention" so that this is the new Wizard "Cast a Spell".

When you release a spell you've prepared, roll+INT.  On a 10+ the spell is successfully cast and costs you no additional price.  On a 7-9, the spell is cast, but choose one:
* you draw the unwelcome attention of an unearthly power or its servants
* the spell disturbs the fabric of reality as it is cast - take -1 ongoing to Cast a Spell until you Prepare Spells again
* you must pay 1 Sanity point to cast the spell

I'd probably also ramp up the weird on the second option, describing corruption and strange stuff happening to the Wizard so long as the -1 was present.

If spells are significant sanity sink, it'd be cool if everyone could cast spells (for cost) but the wizards had, perhaps, a better way of getting sanity back.  That way other classes could cast a couple spells over the course of the game but it would use up some of their very limited sanity.

Wizards are more sane? That dog won't hunt monsignor!

If you go the "everyone can cost spells" route, then the highest level of spell you can cast should be be inversely proportionate to your Sanity.  E.g. anyone can cast a rote.  To cast a 1st-level spell, you must have taken 1 Sanity damage (or sacrificed 1 Sanity to do so).  To cast a 3rd-level spell, you must have taken 3 Sanity damage/sacrificed 3 Sanity.  Something like that. 

Or... take a page from Unknown Armies.  You get hardened to certain levels of cosmic weirdness.  If you cast a spell beyond your "hardened" rating, you might wig out and/or get more hardened.  But the more hardened to cosmic weirdness you are, the more insane you are as a baseline. 

Not sure how to model that "baseline insanity" mechanically... something like Alignment moves or keys might work. 

@skinnyghost: "Secrets Man was not Meant To Know: When you cast a spell on a 7-9 you may also choose: ..."
Also that corruption and aberrant reality (shadows that bear extra appendages and tend to do horrible things to other people's shadows, eyes randomly oppening on surfaces about you ... watching, nightmares to all that sleep within 100 yards, all cats in the town stop and stare at you as you walk by, always) ... yes.  Just yes.

@sage: Depends on your genre/setting.

Most of the Cthulhu genre assumes that wizards have more 'sanity' because they need to train themselves to stay sane (compartmentalize) in order to bind, channel energies that are from beyond the stars.  However this higher-influx of the Dark and Deep Dreaming, this study of the maleficent, maddening and abhorrent knowledges has it's cost.  Most spells bound, are bound into your very mind.

So you might start with more sanity, but for you to be special, for you to be useful, for all the horrors you witness to have meaning - you have to learn the spells.  Which more often than not means permanent loss of sanity as you learn things, and temporary loss as you cast, or bind energies into your mind.

Also you could just stop.  You really could.  If you wanted to.  Really. But once you see them, they see you.  And they come for you.  And now you're without spells ...

Literally the reason wizards run around wide eyed and wild haired is because they are holding words that darken the sun, and make the ears of all present bleed black inside their mind only inches away from their own consciousness.

So maybe it costs you permanent sanity to learn certain spells, or temporary sanity to study them every morning.

Frequently, in fiction, it's not the casting that breaks you, it's seeing the effects.  Or maybe you just need something to bleed "most of" the corruption into that doesn't have sanity to shatter.  How do you guys feel about familiars?

Yes!  I totally want insanity alignments!
Use vegetables to solve a problem
Run screaming and waiving your arms
Help someone understand your gibberish
Discover something mundane during a crisis
Do something inappropriate during a moment of solemnity
Start another fire
Do something for the third time

Oh, yeah, it totally costs sanity to learn a spell.  When you study a spell, your insanity alignment replaces your regular alignment until the spell is cast, taking those otherworldly colors from your mind.