- an attitude of "most patients are just trying to wring medications out of you" - an ego-hit of "if I didn't make the diagnosis, I don't want to help" (this applies to both patients coming in with a suspicion of what they have, or getting a diagnosis from another doctor) - burn-out/overworking, where doctors have a hard time managing all the different cases coming at them without dropping the ball here and there
It's not a simple, single-cause problem at all, but just want to provide an alternative point of view about patients who look things up or come in asking about a specific condition or diagnosis.
When I got my ADHD diagnosis after a quarter-century, I went in specifically asking about ADHD because I had seen some flags that made me think I might have ADHD. Contrast that with the people doctors screen out who are trying to get a stimulant prescription despite not needing it, and you have a situation where it's hard for doctors to tell who does or doesn't need meds, and where patients with actual conditions have to fight hard for those to be diagnosed.
Even in cases like POTS, which has no medication involved in treatment, just lifestyle changes, and yet people close to me who have POTS all had an uphill battle getting it recognized by anyone, especially doctors who could diagnose (disclaimer: sample size = 3).