Given that virtually any staff member in the vast majority of facilities that you will be working, is required to be drug screened, repeatedly, sometimes without warning, it is logical that you will be screened.
If they require the housekeepers that empty the garbage and dietary techs that delivery trays to pass drug screens, it is only natural that they require it of those in jobs of greater concern.
And it begs the question. If you cannot give up illegal, or nonprescribed drugs, long enough to pass a simple drug screen, is being an MD all that important? If it is important enough, you will stop using, or produce a legal script.
There are certain prices that we pay to work in healthcare. One is that we obey the law with regards to some behaviors. It does not matter whether MJ should be legal or not....what matters is that it is illegal, and if you want to work in healthcare, you cannot use.
And I get screened 1-4 times per year and have always passed. And I use SSRIs, eat poppyseed bagals, and have ocasionally been on codeine for cough. No problems.