User blog comment:Corelie/Ambiant Demonic Energy Corruption in D&D Pathfinder/@comment-26869585-20150902185341/@comment-25575899-20150902235752

"Its not actualy permanant it can be removed via a spell such as restoration and lesser restoration"

So, it's permanent damage, because clerics run out of spells prepared per day. Considering the frequency of the damage inflicted, under your system, it is effectively permanent.

That, and how are you going to encode effects that actually would cause wisdom drain in-setting i.e. inhalation of a mothman's wing scales?

In general, applying effects that damage stats or inflict negative levels are only handed out against really strong monsters, not the run of the mill monster you'll find outside the city gate.