Do insurance companies suddenly cut you off of anti-depressants and other psych medications?

I have a friend who is reluctant to even try an anti-depressant because she might suddenly be told, "sorry, no more refills".

I thought it was extremely important to taper off most psychoactive medications, instead of stopping all of a sudden. And that even as assholic the insurance companies are, they wouldn't do this. Or am I naive to think they have even an ounce (or gram) of humanity?

Thankx

Edited to add - she's insured through Minnesota's Medicaid program, administered (and whatever else), in her case by Medica.