A psychiatric-mental health nurse practitioner is an American advanced practice nurse who assesses, diagnoses and treats mental illness and, in most states, prescribes medication entirely independently, without requiring sign-off from a physician for routine prescribing decisions.
A substantial share of US psychiatric care
PMHNPs hold a master's or doctoral qualification alongside national board certification, and in many parts of the United States they provide a genuinely substantial share of overall psychiatric care, reflecting how the American healthcare system has come to rely on advanced practice nursing to fill gaps in psychiatrist availability, particularly in areas with fewer psychiatrists.
Does not transfer to UK practice
This is an American credential specifically, and it does not transfer to UK practice in any form, since the regulatory structures and training pathways involved are entirely separate from the UK system. For anyone in the UK looking for the closest equivalent, the advanced nurse practitioner role and the nurse independent prescriber working in mental health are the nearest comparable positions, though the training route to get there differs from the American PMHNP pathway.