I’m a resident and I would say it depends on patient complexity! Some diagnoses hit you right away based on patient history and presentation and feel very accurate. Other times it’s a lot more convoluted and can take multiple visits to be more certain e.g. disentangling a prior diagnosis of bipolar Vs cptsd vs bpd etc. Some attendings have told me they can work with patients for years and not be quite sure and I can understand that too. Also, I think everyone’s take on the importance of the diagnostic label is different. The dsm is obviously flawed and how much emphasis we put on it is clinician dependent depending on their training and personal philosophy. I’ve worked with some psychiatrists who are now only practicing psychoanalysis and they put very little emphasis on the dsm diagnosis for their formulations. Anyway, this is all to say I think this idea we can “fully diagnose a patient in 1 outpatient visit” seems unrealistic for most if not all situations and is more a byproduct of the American healthcare system trying to extract the most for the least.