I call out of work and tell them I'm "sick" and need a few days off when I'm manic and not doing well. I have a physical condition that I use as my excuse so I can get a doctor's note from my pcp to make it seem valid. When I got hospitalized ( 3 times so far) I used different excuses and got a note from the hospital claiming I was there, but it didn't specify why though for patient confidentially. I would recommend that you don't tell your boss anything about your mental condition, only physical conditions if you have any. Mental illness are taboo in the work field and may be viewed as a liability.