Mental Health: question about Job drug testing and psychiatric medication?

[Gabe]

I have an interview tomorrow at the Sheriff's department. I may have to take a drug test as well. I'm prescribed different medications, one of which is Invega, an anti psychotic used at night to sleep mostly. I take it on occasion only as needed. I will tell them the name of the medicine and about the last time i took it, but do they test for anti psychotics? And could they question me on why i was prescribed that and use it against my employment? Thanks