Psychiatrists can [should] treat diagnoses rather than symptoms. By that I mean, (1) maintaining a differential that includes medical, neurologic, pharmacological causes of symptoms - and doing something about those causes. And (2) using a similar kind of strategy, learned in medical training, even when the illness IS “purely psychiatric.”
Regards to (1)
In my experience NPs don’t often consider that a medication (whether it’s one they had prescribed or not) might be the cause of a symptom, and they reflex to adding another medication. I’m less sure how often they work up basic medical causes of symptoms, e.g. hypothyroidism. I think it’s very unlikely that they would think of something like anti-NMDA encephalitis in a 40yo with new psychosis and facial twitching, and would just prescribe an antipsychotic rather than arranging for the LP per Neuro.
Regards to (2)
If you’re keeping an open psych differential you might find that after 8-10 outpatient appointments, what you thought was MDD because of the SI and reported low mood, was really Avoidant Personality Disorder all along, where the SI is a chronic, escapist fantasy as a coping mechanism, and the low mood (which was never really evident by their affect in the first place, you realize) is really what they were calling the effects of their anxious attachment style on their life circumstances. This changes management.
But this does not happen when treatment is guided essentially by self report symptom surveys.