I was unaware that psychologists are required to report anyone they treat. OR, that they are required to keep a list of their patients. What about a patients right to privacy ?
Considered part of the medical profession, they have a duty to report anyone they consider to be a danger to others, but that's a line that can't be easily tied down, and the records can be obtained by law enforcement given the right set of circumstances. Otherwise, no, it's not public information, but those with the power to take your rights away can access it. In the event that the mental health treatment is paid for through insurance or a company's medical health policy, there's a starting point.
When the government is interested in involving itself in every aspect of our lives, we can't be honest with our doctors anymore. What do you think it will be like when all healthcare will be government healthcare? As it is, whenever I go in for my annual checkup, they ask questions about depression, whether or not I have ever considered harming myself or others, and whether I own any firearms. Since we're in Maine, where we don't register our firearms, my doctors have always told me that I didn't have to answer that question, and I don't.
To be real with it, I doubt seriously if there are very many who hasn’t thought about harming themselves at one time or another ergo very few of us can answer that question truthfully. Given the tools, a hormonal monster called a teenager is more apt to either hurt themselves or someone else. If anything, I wouldn’t be concentrating on the adult applicant so much as to ask how many kids are living in the home and what kind of plan is there to keep a weapon from the hands of pubescent kids.