Open Question: can health insurance companies request medical records from other health insurance companies?

When I was in college I was in a relationship that made me really depressed, and the psychologist on campus referred me to an outside therapist with a diagnosis of "major depression"--the outside therapist corrected it and said she believed i had circumstantially-related depression, but she told me she coded the claim with the referring guy's "major depression" label so the insurance company wouldn't hassle me about the paying the claim. I worked with her for a 6 months --no medication, just got out the relationship--and am happy and healthy :) Now I'm reading all kinds of scary stuff about MIB, retroactive declining of coverage, etc and I currently have new individual (underwritten) coverage--I can ask her to correct the claim with my old company, but it seems like any action might rock the boat and I'm scared--if they didn't notice it, should i leave it be? or is there a chance that if i (god forbid) get something serious down the road that my current insurer will dig up my records from my old insurer to look for a reason to not pay? she was trying to do something to make my life easier but this whole thing has turned into such a mess!