Editor's note: Inc.com columnist Alison Green answers questions about workplace and management issues--everything from how to deal with a micromanaging boss to how to talk to someone on your team about body odor.

A reader writes:

I've just been put in charge of hiring a group of staff for a summer camp. I began managing this group of staff last May (and was thus not involved in the hiring process) and discovered that a couple staff members had some mental health issues that interfered with their job responsibilities. Two of the most extreme examples involved one worker with an eating disorder and cutting; another had PTSD. This really impacted their ability to be good counselors -- the first as a role model to impressionable junior highers; the second was afraid of the dark and would have serious flashbacks, making overnight camp-outs impossible.

Now that I'm playing a more significant role in hiring, I'd like to know what I can do in the interview process to find out about these sorts of things. While both of these workers underwent extensive reference checks, this isn't the kind of thing that regular employers would find out about. Is it prudent for me to ask direct questions about a potential counselor's current mental health? I want to hire emotionally stable people, but I'm worried about being discriminatory.

Oooh, this is tricky. The law doesn't allow you to inquire into someone's medical health, but you can ask whether they can perform specific duties. I asked employment lawyer Donna Ballman, the author of Stand Up For Yourself Without Getting Fired, to weigh in on the best way for you to proceed. Here's her advice:

"Pre-employment, the employer may not ask questions that will disclose the existence of a disability. What they can ask are questions about their ability to perform specific tasks. For instance, it's a legitimate question to ask what they would tell a camper who became fearful on an overnight camping trip, what their favorite things to do on a camp-out are, and what activities they like to do with the kids. They could be asked what experience they have helping kids work through problems, what they'd do if they encountered a camper who clearly had an eating disorder, or why they are the best person to supervise children.

The appropriate thing to do when in doubt is make a conditional offer of employment. After the conditional offer is made, the employer may do some things that may help under these circumstances, as long as they are done for all employees who get the conditional offer. They could do a physical agility test requiring them to demonstrate their ability to perform certain skills, as an example. They could require the individuals to demonstrate skills such as the ability to start a campfire in the dark, how to make s'mores, or other basic camping skills. If the post-employment inquiry discloses the existence of a disability, the employer can now ask how the applicant will be able to perform the essential duties of their job and what accommodations the employer may need to provide.

The main thing I'd caution is to not make assumptions about someone's abilities just because they have a disability. For instance, the employee who had an eating disorder might well be able to recognize a camper with the beginnings of one and help get them through their problem or know when to call in a professional for help. The employee who was afraid of the dark might be able to help campers through their fears. If it is clear the applicant will not be able to perform the essential functions of their job, even with accommodations, then the offer may be withdrawn."

In addition to Donna's excellent advice, this is also probably a situation where "tell me about a time when..." interview questions will be especially important. For instance, ask about past overnight camping trips (and what has made them most anxious during those times, and how they handled that), about experience identifying and helping struggling peers, about their own experience in overcoming challenges (of any type), about how they'd model healthy eating habits for campers, and about any other behaviors and traits you want to make sure they demonstrate.

In fact, this should help you make better hires across the board, and not just in the sorts of cases that you're asking about here.

Want to submit a question of your own? Send it to alison@askamanager.org.