Here are some of the original approaches to simulate Sanity in Fudge:
Unfortunately those aren't available under the Open Game License so you'd need to contact the original authors for permissions.
Grey Ghost Press, Inc.
The old Fudge Factor had an article that gave a system for Fear Checks that could give a character a psychological problem.
http://wayback.archive.org/web/20080516 … hecks.html
http://wayback.archive.org/web/20071024 … sited.html
The Guidline Gazette for Terra Incognita Vol. 2 had some fear rules that are a modifications of the above James Wedig ones and had some info on Victorian Age and Pulp Era therapy.
http://web.archive.org/web/200612300539 … aghund.de/
Another Fudge Factor article
http://wayback.archive.org/web/20060831 … y_mad.html
A Magical Medley has some Sanity rules in the Occultism chapter.
None are OGL.