Working in Drug/addiction Rehab Centers?

I’m currently a human development and family studies major but I have an undecided minor. I personally would like to be the one who’s in direct contact with patients during their withdrawal phases and being able to monitor them. I’m pretty sure that’s vague, but what job title is that specifically? In order to pursue this career would a biology minor benefit me more, would I need to go to medical school, what about grad school?

If it means anything I go to school in Nevada and I’d greatly appreciate some input and opinions.