Both codes report an initial psychiatric diagnostic evaluation. The difference is three words in the descriptor: with medical services.
90791 is the evaluation without medical services. 90792 is the evaluation with them. If you have prescribing authority and you performed medical work during the visit, 90792 is your code. For most PMHNPs, most of the time, that is where the question ends.
The decision that actually costs prescribers money comes after that one, and it is the second half of this article.
What Both Codes Require
90791 and 90792 replaced the older psychiatric diagnostic interview codes in 2013. Regardless of which one you report, a psychiatric diagnostic evaluation includes:
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A comprehensive medical and psychiatric history, including past, family, and social history
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A complete mental status examination
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A diagnosis or diagnostic formulation
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A preliminary treatment plan
The evaluation may also include communication with family members or other sources, and the ordering or interpretation of diagnostic studies.
These are intensive encounters, typically reported once per patient per provider per episode of care. Frequency rules vary by payer, so confirm how yours handles repeat evaluations and transfers of care.
90791: Without Medical Services
This is the code used by non-prescribing behavioral health providers, including licensed clinical social workers, licensed professional counselors, licensed marriage and family therapists, and psychologists.
It is also the correct code for a prescriber whose evaluation genuinely included no medical services. That is uncommon in psychiatric practice, but it exists.
90792: With Medical Services
This is the initial evaluation code for prescribers. Physicians, nurse practitioners, and physician assistants can report it. Non-prescribing providers cannot, regardless of how thorough their evaluation was, because they cannot act on medical information pharmacologically.
Medical services generally include:
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Medication management. Reviewing the current regimen, assessing response and tolerability, screening for interactions with non-psychiatric medications, and making a pharmacologic decision with documented rationale.
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Physical assessment. Vital signs, evaluation for extrapyramidal symptoms, assessment for signs of withdrawal, or any focused physical examination relevant to the presentation.
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Diagnostic testing. Ordering, reviewing, or interpreting labs or studies such as a thyroid panel, metabolic panel, toxicology screen, EKG, or EEG.
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Medical decision-making. Treatment planning that accounts for the interaction between the psychiatric presentation and comorbid medical conditions.
Writing a prescription is one form of medical service. It is not the threshold. A documented decision to hold off on starting a medication until you have lab results is medical decision-making, and it belongs in a 90792 note.
The Audit Risk Is Undercoding in Disguise
Your credential determines which code you are eligible to bill. Your documentation determines which one you actually billed.
If a reviewer opens your intake note and finds a strong history and mental status exam but no medication assessment, no physical findings, no labs, and no pharmacologic reasoning, the note supports 90791. Your license does not change that.
Before you close a 90792 note, check that a reviewer who has never met you could point to the medical work on the page:
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Current medications reviewed, psychiatric and non-psychiatric, with any interaction concerns noted
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Physical assessment findings or reviewed vital signs, actually written down
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Labs or studies ordered or reviewed, with the reasoning behind them
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How comorbid conditions shaped the diagnosis, the medication choice, or the monitoring plan
The Decision That Actually Costs You: 90792 or an E/M
Here is the part almost nobody writes about.
A new patient psychiatric evaluation can be reported as 90792, or as a new patient office E/M service such as 99204 or 99205. Both are diagnostic encounters focused on assessment, formulation, and treatment planning. Both are legitimate. Most PMHNPs default to 90792 without ever considering the alternative, because 90792 is the code that gets taught as the psychiatric intake code.
The consideration that should drive the choice: 90792 does not allow psychotherapy add-on codes.
If you deliver distinct, time-supported therapeutic work during an intake, billing 90792 gives you no mechanism to capture it. Reporting an E/M instead keeps the add-on available.
That said, psychotherapy is less commonly billable at intake than providers expect. Initial evaluations are diagnostic by nature, and psychoeducation or supportive discussion during an intake does not automatically meet the standard for add-on psychotherapy. The intervention still has to be distinct from the diagnostic work and supported by time.
Reimbursement between the two pathways varies by payer, geography, and contract. Check your own fee schedule rather than assuming one pays better.
If You Go the E/M Route
New patient office E/M codes can be selected two ways: on total time for the date of service, or on medical decision-making. For a straightforward intake with no psychotherapy, either pathway is available and you use whichever the visit supports.
That changes the moment you add psychotherapy. If you report an add-on psychotherapy code with the E/M, the E/M level must be selected on medical decision-making. Time is off the table. Psychotherapy is the time-based service, and the same minutes cannot support both.
This is the step providers miss. They deliver the intake, add the psychotherapy code, and then select 99205 based on how long the visit ran. That combination does not hold up, because the E/M was never supported by MDM in the first place.
Selecting on MDM means Problem, Data, and Risk each have to be documented on their own terms. Each has its own criteria, and each is scored independently.
The Bottom Line
90791 versus 90792 resolves quickly. If you performed medical services and documented them, it is 90792.
The harder question is whether the initial evaluation should be reported as 90792 or as an E/M, and the answer depends on whether therapeutic work is part of how you practice. That question repeats at every follow-up visit after the intake, which is where most of your notes get written.
Want to code follow-up visits with the same clarity?
The Psychotherapy Documentation and Coding Handbook covers E/M level selection by medical decision-making, add-on psychotherapy documentation, and the reference tables that make both faster to apply. Written for PMHNPs, by a PMHNP.
Crystal Stone, PMHNP-BC, FNP-BC, CPMA, CPC, and CPB of New Leaf Billing, Coding, and Auditing Solutions, LLC, conducted an independent content review of the Psychotherapy Documentation and Coding Handbook for general alignment with documentation and coding standards.
This content is intended as general educational information and does not constitute coding, billing, or legal advice. Coding requirements and payer policies vary by plan, state, and setting. Providers should verify requirements against current CPT, CMS, and payer-specific guidance, and should follow the documentation, supervision, and scope-of-practice requirements applicable to their licensure.