I've been off work for six weeks or so, seeking treatment for post-traumatic stress disorder (PTSD) related to my military service. Although my condition was debilitating at onset, I feel much better now and am fully able to return to work. My employer is insisting that I take a fitness-for-duty exam before I can go back. Is this legal? It seems like my employer is assuming that I can't be trusted to handle myself just because I have a mental condition.