Are you talking about your GP or a pdoc? That would be the difference to me.

My GP knows what meds I take, but he NEVER asks me about my mental health issues unless I specifically bring it up. All he needs to know is what meds I'm taking (he can figure out why on his own; it's not rocket science) so anything he prescribes doesn't interact wrongly. I've been seeing him for years, and he did initially help me with antidepressants, but I moved on to a pdoc to handle my mental health issues fairly quickly.

Now if you are talking about a pdoc, I'd say he would obviously need to know about your therapy. Completely different scenario.