Do you think the vague `medical` needs further elaboration?
I sure do know my medical is not related to mental health.
Is it reasonable to somehow indicate that or it should be better left for an interviewer to inquire?
In the USA I am pretty sure it is actually illegal for a company to discriminate based on health issues, so a smart recruiter will NOT push this issue further than Medical. It would violate a few things and not be great if you sued and used that in court.
Legally, they can't, but the fact that you were out for months for an unspecified medical issue suggests you're likely to have more medical issues and thus would be a reason to be less likely to hire you.
Really they should accept that as it is and move on. You may want to reassure them that the medical issue is resolved, assuming it is, and you too, move on. If you're in the US, then they aren't even allowed to ask more questions. You're not obligated to even mention it was medical, for that matter.
It is perfectly legal to ask, but that opens you up to accusations that you also discriminated. You no longer have the defense that you didn't know the information, and the court would want an explanation for why you were asking.
It's hard to imagine an illegal question under US federal law, but I suppose there could be one where the question itself is sexual harassment or an attempt at stealing trade secrets.
I sure do know my medical is not related to mental health. Is it reasonable to somehow indicate that or it should be better left for an interviewer to inquire?