I am at a point in my career where I foresee me being involved in interviewing and hiring within the next 5 years. I am already involved in some manner with the process of terminating people because I distribute work and my input is sought regarding specific employees who are not performing well.
Personally, I regularly have to deal with a mental condition that has a heavy stigma tied to it. I deal with it in a manner that works for me to the point that I foresee positive things on the horizon regarding my career. I do not reveal this condition because I don't want my career to take a hit.
I can say that getting to the point I'm at with my personal mental condition required a lot of work on my part and would've been a lot easier if it were possible for me to be forthright about it and get appropriate accommodations. Some of the people whom I've had to give negative reviews on and were later terminated, I strongly suspected there may be an underlying mental condition.
I don't think you can ask someone directly if they have a mental condition because this is a workplace, but can someone pro-actively inquire if any special accommodations are required (even if an employee did not request accommodation)? I don't mean a general question like, "Is there anything you need?" I'm specifically referring to a scenario where the employee has some sort of invisible condition that the ADA would require accommodation if requested. I would prefer to proactively inquire about their need for accommodation without requiring them to disclose whatever reason they need the accommodation.