In your scenario, the person has volunteered that she is depressed. Does the mission want to exclude her automatically? There are two problems with this. First, if the ADA applies, automatic exclusion probably violates it. Second, as followers of Christ, do we want to signal that people dealing with mental health issues are second class or unacceptable to us—that these problems are somehow worse than other problems? I’d prefer that we start from the perspective of considering whether the person can be supported in a missions placement—or at least some, if not all, placements.
But what if the condition seems serious enough that the mission is truly concerned that it will not work out well? Keep in mind that many job descriptions may make it clear that the job falls under a ministerial exception. The mission can require certain levels of spiritual and emotional behavior/maturity, which is hard to challenge under the ADA, because of case law.
Second, bona fide occupational qualifications for a mission organization may include levels of spiritually maturity or functional behavior, if written into the job description. It is fair to ask if a disabling mental health condition will keep the individual from meeting these bona fide occupational qualifications. In other words, the legal requirement for a person with a disability is that she be able to perform the functions of the job, either with or without accommodations.
Next, consider the concern of whether particular job placements would jeopardize either the individual’s safety and health or the safety and health of the persons around her. Organizations are not required to jeopardize anyone’s safety in accommodating disabilities. There may be placements where mental health issues can be addressed, and others where they cannot be.
If the mission has concerns over whether the individual can perform the required functions of the job, it should also think about whether she could perform with accommodations. What might the accommodations be? More frequent trips “out” of the stationed area? More supervision by the team leader? A longer language study schedule?
The organization doesn’t necessarily have to give the individual any accommodation she can come up with, and the accommodation need not be an undue burden on the organization, but it is wise to have an interactive discussion with the individual.
If more supervision or support is going to be a possible accommodation, you then have the issue of whether the person wishes to consent to have her medical/psychological condition shared with supervisors or teammates. She has that choice. (If she accepts this accommodation, you are right that she should sign releases to share that information.) On the other hand, if she doesn’t want to agree, the mission might determine it cannot safely support her in those settings.
If the field placement will not work, at least consider whether there might be an appropriate different placement, in another field, or in the home office. The mission is not absolutely required to create a job, but should at least work through the analysis in good faith. It wouldn’t want to reject everyone who has psychological issues—not only for legal reasons, but presumably also for spiritual ones.
Disclaimer: not official legal or psychological advice or opinion