My T says I can call her by her first name, or even go "Hey".

I tend to call her "Dr FirstName" though, because I feel I have to respect the fact that she's earned a PhD in clinical psychology.

We're Asian and I would feel uncomfortable just addressing her by her first name.

But I feel comfortable with her so I don't address her as "Dr Surname " like I would for other clinicians.

This is despite how she's only a couple of years older than me and we're both under 30.

She calls me by my first name. If she addressed me as "Ms Surname ", I would feel awkward, like she's equalizing us, and it would be too formal.