before i applied for my permit, i actually went back and read over the confidentiality agreement i signed with my therapist. it said that she would never disclose any information, blah blah blah, EXCEPT as required by law or pursuant to police investigation, or something like that. i recall reading it to mean that if my investigator called my shrink, she would be required by law to answer every question he asked. i decided this was fine for me, since i had nothing to hide, and i imagine that unless your stress is manifesting as murderous or suicidal rage you'll be fine too. it seemed like there was a much bigger risk associated with not mentioning the therapy on my application--oversights and/or lying are instant rejection, and they are looking for any possible reason to reject you.
i have no idea if my investigator actually called my shrink though. i don't talk to her anymore.