Originally Posted by medium rare
You do both by meeting the training and licensure/certification requirements for both credentials in your state. Being licensed as a psychologist will in no way negatively impact your ability to practice as a psych NP - it's "both/and not either/or."
If your state requires NPs to have a collaborative agreement, then you must abide by the terms of that agreement with regard to those aspects of practice that are specific to your NP role. Keep in mind however, a collaborative agreement is not "supervision." It usually means that there is something written on file with the Board of Nursing stating how the NP will use the identified collaborating physician - in most cases, it is the NP's decision to contact the collaborating if needed. There are only a few (2-3 state) that still require actual physician "supervision."
If you're a prescribing psychologist in NM or LA, then you don't need to get the NP. If you are already a psychologist/NP and are in a state that certifies prescribing psychologists, you can qualify for a prescribing psychologist certificate, but you should only prescribe under one credential - there would be no need to do so under both NP and prescribing psychologist status. Same thing as a physician, NP, PA, etc. You can only Rx under one professional credential.
Unless you are certain you want to live in NM or LA, you should consider getting the NP credential.
Thanks for clearing up information. It seems that many psychologists, including psychology doctoral students as myself are not certain of how working as a licensed psychologist and NP works. My advisors and other psychologists have informed me that you could not use both licenses in the State of Texas.