Psychiatric / nursing question?

A friend of mine had an appointment with someone in the psychiatric field. I thought the guy was a Psychiatrist, but, after his name was RN, CS. I assume this stands for registered nurse, clinical or certified specialist, anyway, this guy was able to write prescriptions. I was hoping someone could explain me what this guys title may be.

tossed the "rn, cs" in a search browser and this is a link that got thrown back at me.. looks like it might be what you are looking for if you need an example of what the specialty might be.. it fits well.
http://www.dianehaber.com/

In certain states, RN's who have their masters degrees (suh as nurse practitioners) can write scripts. They have gone through more training than a regular RN, and have been trained in the prescribing of medications. They are highly specialized and trained. Trust me, the know what they're doing!

In USA, clinical nursing staff who are trained and certified in psychiatry, to a certain degree, can prescribe medication.

This person is an RN with a master's degree. If your friend is having psychiatric problems he needs to see a psychiatrist.