It does pretty well on ChatGPT4 - I would say the main thing is that you have to be a bit more directive with it than you would be with a therapist.
Obviously a real therapist would consider in advance what the goal / focus of that session should be (although often they will ask you...). You have to lead AI a bit more by saying things like "In this session I'd like to focus on XYZ problem"
Also it's better to be willing to probe its answers a bit more (I think this happens naturally in face to face therapy but you need to specifically think about doing it with AI).
For example - I had a session which led on to self-care and I wanted it to make some suggestions to me (as in concrete advice/options).
It was happy to do this and I could have just left the conversation at a list of the ten options it gave but in reality I started thinking about lots of barriers.
How some just wouldn't work in my schedule, how I didn't like some of the others for various reasons, etc.
I gave it that feedback and it helped me to find other options that would fit my lifestyle / be more appropriate / find ways to make it work.
It does require some 'meta-cognition' and self-awareness though.
In that example, I need to notice that I was feeling bratty and just mentally pushing back on all the options and then ask it to help me work it through.
I've only been doing it for a couple of days, I'll probably write a post about it in a few more days as it might be an option to help people who have less severe MH issues and/or that need some input while waiting for better options and have a good level of self-awareness.
I wouldn't recommend at this stage for very serious MH issues though (not for any specific reason, it would just worry me that it could say something that makes things worse and obviously can't see what impact that's had on the person using it and adjust its approach!)