Why is this thing a nil value?

[Sacco]

So, i was trying to give Wolfgang a higher sanity drain the lower his sanity is.

local function onsanitychange(inst, data)
    local sanityboost = 1
    if inst.components.sanity:GetPercent()<0.50 then
        sanityboost = 1.5
    end
end
GLOBAL.TUNING.WOLFGANG_SANITY_NIGHT_DRAIN = 1.25 * sanityboost

AddPrefabPostInit("wolfgang", function(inst)
    if GLOBAL.TheWorld.ismastersim then
        inst:ListenForEvent("sanitydelta", onsanitychange)
    end
end)

But when i try to load a world this error shows up:

attempt to perform arithmetic on global 'sanityboost' (a nil value)

I don't understand the reason, can someone explain why and help me fix it?

Thanks!

[Baguettes]

You defined sanityboost inside a function, and it'd only work within that function! D:

Either you move the global tuning into the onsanitychange function, or you move the local sanityboost out of there for it to work.