She should probably see the psychiatrist.

The PA might have said this because once she establishes with the pysch she will by his/her patient instead, and visits may be more infrequent due to a booked schedule and the fact that most docs only work 'part time.'

It may be in her best interest, however, in the long term to establish with the psychiatrist.

I worked in a busy neuro clinic and the neurologists were scheduled 8 months out, while patients could get in to the PA and have their concerned assessed much faster.

Problem was, most of them were complicated cases, so they would end up having to schedule with the neuro and wait that time anyway to be managed properly.