I was given this when I first started in BH coding and was guidance published when these codes were implemented in 2013:
From the APA’s CPT Primer for Psychiatrists:
90792 This code is used for an initial diagnostic interview exam for an adult or adolescent patient that includes medical services. It includes a chief complaint, history of present illness, review of systems, family and psychosocial history, and complete mental status examination, as well as the order and medical interpretation of laboratory or other diagnostic studies.
From 2013 Psychiatry CPT Codes. American Academy of Child and Adolescent Psychiatry. 2012.
90792
Psychiatric diagnostic evaluation with medical services is an integrated biopsychosocial and medical assessment, including history, mental status, other physical examination elements as indicated, and recommendations.
The evaluation may include communication with family or other sources, prescription of medications, and review and ordering of laboratory or other diagnostic studies.
Medical thinking: note that this is not specified in the code description, but represents the AACAP intent during the code development process.
Medical thinking is likely the main component that differentiates an evaluation by a psychiatrist, APN, or PA from one by a non-medical provider.
Includes consideration of: medical history and comorbidities, medications prescribed by others, further medical work-up, medical treatments, integration of signs and symptoms from a medical standpoint.